[libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98075)

This is a part of #97655.

80 files changed, 263 insertions, 160 deletions

diff --git a/libc/src/stdlib/_Exit.cpp b/libc/src/stdlib/_Exit.cpp
index 03a7662..859598c 100644
--- a/libc/src/stdlib/_Exit.cpp
+++ b/libc/src/stdlib/_Exit.cpp
@@ -8,13 +8,14 @@
 
 #include "src/__support/OSUtil/exit.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
 #include "src/stdlib/_Exit.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 [[noreturn]] LLVM_LIBC_FUNCTION(void, _Exit, (int status)) {
   internal::exit(status);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/_Exit.h b/libc/src/stdlib/_Exit.h
index bc05faf..398ab53 100644
--- a/libc/src/stdlib/_Exit.h
+++ b/libc/src/stdlib/_Exit.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB__EXIT_H
 #define LLVM_LIBC_SRC_STDLIB__EXIT_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 [[noreturn]] void _Exit(int status);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB__EXIT_H
diff --git a/libc/src/stdlib/abort.h b/libc/src/stdlib/abort.h
index d3bf1e9..2bb292b 100644
--- a/libc/src/stdlib/abort.h
+++ b/libc/src/stdlib/abort.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_ABORT_H
 #define LLVM_LIBC_SRC_STDLIB_ABORT_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 [[noreturn]] void abort();
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ABORT_H
diff --git a/libc/src/stdlib/abs.cpp b/libc/src/stdlib/abs.cpp
index 6be63e0..688c504 100644
--- a/libc/src/stdlib/abs.cpp
+++ b/libc/src/stdlib/abs.cpp
@@ -9,9 +9,10 @@
 #include "src/stdlib/abs.h"
 #include "src/__support/common.h"
 #include "src/__support/integer_operations.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, abs, (int n)) { return integer_abs(n); }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/abs.h b/libc/src/stdlib/abs.h
index 19cef14..56ab04b 100644
--- a/libc/src/stdlib/abs.h
+++ b/libc/src/stdlib/abs.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_ABS_H
 #define LLVM_LIBC_SRC_STDLIB_ABS_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 int abs(int n);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ABS_H
diff --git a/libc/src/stdlib/aligned_alloc.h b/libc/src/stdlib/aligned_alloc.h
index 7f294c8..0205c02 100644
--- a/libc/src/stdlib/aligned_alloc.h
+++ b/libc/src/stdlib/aligned_alloc.h
@@ -6,15 +6,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/macros/config.h"
 #include <stddef.h>
 
 #ifndef LLVM_LIBC_SRC_STDLIB_ALIGNED_ALLOC_H
 #define LLVM_LIBC_SRC_STDLIB_ALIGNED_ALLOC_H
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void *aligned_alloc(size_t alignment, size_t size);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ALIGNED_ALLOC_H
diff --git a/libc/src/stdlib/at_quick_exit.cpp b/libc/src/stdlib/at_quick_exit.cpp
index 752d67e..7acae8c 100644
--- a/libc/src/stdlib/at_quick_exit.cpp
+++ b/libc/src/stdlib/at_quick_exit.cpp
@@ -9,9 +9,10 @@
 #include "src/stdlib/at_quick_exit.h"
 #include "hdr/types/atexithandler_t.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/exit_handler.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, at_quick_exit, (__atexithandler_t callback)) {
   return add_atexit_unit(
@@ -19,4 +20,4 @@ LLVM_LIBC_FUNCTION(int, at_quick_exit, (__atexithandler_t callback)) {
       {&stdc_at_exit_func, reinterpret_cast<void *>(callback)});
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/at_quick_exit.h b/libc/src/stdlib/at_quick_exit.h
index c36c797..0bfd4ff 100644
--- a/libc/src/stdlib/at_quick_exit.h
+++ b/libc/src/stdlib/at_quick_exit.h
@@ -10,11 +10,12 @@
 #define LLVM_LIBC_SRC_STDLIB_AT_QUICK_EXIT_H
 
 #include "hdr/types/atexithandler_t.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 int at_quick_exit(__atexithandler_t);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_AT_QUICK_EXIT_H
diff --git a/libc/src/stdlib/atexit.cpp b/libc/src/stdlib/atexit.cpp
index ca3cbfe..6844fb7 100644
--- a/libc/src/stdlib/atexit.cpp
+++ b/libc/src/stdlib/atexit.cpp
@@ -9,9 +9,10 @@
 #include "src/stdlib/atexit.h"
 #include "hdr/types/atexithandler_t.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/exit_handler.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 extern "C" {
 
@@ -32,4 +33,4 @@ LLVM_LIBC_FUNCTION(int, atexit, (__atexithandler_t callback)) {
       {&stdc_at_exit_func, reinterpret_cast<void *>(callback)});
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/atexit.h b/libc/src/stdlib/atexit.h
index 7faaf65..39ce2dc 100644
--- a/libc/src/stdlib/atexit.h
+++ b/libc/src/stdlib/atexit.h
@@ -10,10 +10,12 @@
 #define LLVM_LIBC_SRC_STDLIB_ATEXIT_H
 
 #include "hdr/types/atexithandler_t.h"
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 int atexit(__atexithandler_t);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ATEXIT_H
diff --git a/libc/src/stdlib/atof.cpp b/libc/src/stdlib/atof.cpp
index 61eb7db..18a65c6 100644
--- a/libc/src/stdlib/atof.cpp
+++ b/libc/src/stdlib/atof.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/atof.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_float.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(double, atof, (const char *str)) {
   auto result = internal::strtofloatingpoint<double>(str);
@@ -21,4 +22,4 @@ LLVM_LIBC_FUNCTION(double, atof, (const char *str)) {
   return result.value;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/atof.h b/libc/src/stdlib/atof.h
index cc9ae51..dfa97c3 100644
--- a/libc/src/stdlib/atof.h
+++ b/libc/src/stdlib/atof.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_ATOF_H
 #define LLVM_LIBC_SRC_STDLIB_ATOF_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 double atof(const char *str);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ATOF_H
diff --git a/libc/src/stdlib/atoi.cpp b/libc/src/stdlib/atoi.cpp
index d1dc320..9e46b53 100644
--- a/libc/src/stdlib/atoi.cpp
+++ b/libc/src/stdlib/atoi.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/atoi.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, atoi, (const char *str)) {
   // This is done because the standard specifies that atoi is identical to
@@ -23,4 +24,4 @@ LLVM_LIBC_FUNCTION(int, atoi, (const char *str)) {
   return static_cast<int>(result);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/atoi.h b/libc/src/stdlib/atoi.h
index fb5de31..218c051 100644
--- a/libc/src/stdlib/atoi.h
+++ b/libc/src/stdlib/atoi.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_ATOI_H
 #define LLVM_LIBC_SRC_STDLIB_ATOI_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 int atoi(const char *str);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ATOI_H
diff --git a/libc/src/stdlib/atol.cpp b/libc/src/stdlib/atol.cpp
index 5586db7..7f3414a 100644
--- a/libc/src/stdlib/atol.cpp
+++ b/libc/src/stdlib/atol.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/atol.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long, atol, (const char *str)) {
   auto result = internal::strtointeger<long>(str, 10);
@@ -21,4 +22,4 @@ LLVM_LIBC_FUNCTION(long, atol, (const char *str)) {
   return result;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/atol.h b/libc/src/stdlib/atol.h
index 690731f..3787dc1 100644
--- a/libc/src/stdlib/atol.h
+++ b/libc/src/stdlib/atol.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_ATOL_H
 #define LLVM_LIBC_SRC_STDLIB_ATOL_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long atol(const char *str);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ATOL_H
diff --git a/libc/src/stdlib/atoll.cpp b/libc/src/stdlib/atoll.cpp
index 921459d..4f1a02a 100644
--- a/libc/src/stdlib/atoll.cpp
+++ b/libc/src/stdlib/atoll.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/atoll.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long long, atoll, (const char *str)) {
   auto result = internal::strtointeger<long long>(str, 10);
@@ -21,4 +22,4 @@ LLVM_LIBC_FUNCTION(long long, atoll, (const char *str)) {
   return result;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/atoll.h b/libc/src/stdlib/atoll.h
index 4746eb1..b3035fdc 100644
--- a/libc/src/stdlib/atoll.h
+++ b/libc/src/stdlib/atoll.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_ATOLL_H
 #define LLVM_LIBC_SRC_STDLIB_ATOLL_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long long atoll(const char *str);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_ATOLL_H
diff --git a/libc/src/stdlib/baremetal/abort.cpp b/libc/src/stdlib/baremetal/abort.cpp
index 4dd8536..98cf710 100644
--- a/libc/src/stdlib/baremetal/abort.cpp
+++ b/libc/src/stdlib/baremetal/abort.cpp
@@ -7,11 +7,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
 #include "src/stdlib/abort.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, abort, ()) { __builtin_trap(); }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/bsearch.cpp b/libc/src/stdlib/bsearch.cpp
index 4292d6b..69b3e74 100644
--- a/libc/src/stdlib/bsearch.cpp
+++ b/libc/src/stdlib/bsearch.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/bsearch.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
 #include <stdint.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void *, bsearch,
                    (const void *key, const void *array, size_t array_size,
@@ -44,4 +45,4 @@ LLVM_LIBC_FUNCTION(void *, bsearch,
   return nullptr;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/bsearch.h b/libc/src/stdlib/bsearch.h
index 3590198..cef37ea 100644
--- a/libc/src/stdlib/bsearch.h
+++ b/libc/src/stdlib/bsearch.h
@@ -9,13 +9,14 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_BSEARCH_H
 #define LLVM_LIBC_SRC_STDLIB_BSEARCH_H
 
+#include "src/__support/macros/config.h"
 #include <stddef.h> // size_t
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void *bsearch(const void *key, const void *array, size_t array_size,
               size_t elem_size, int (*compare)(const void *, const void *));
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif //LLVM_LIBC_SRC_STDLIB_BSEARCH_H
diff --git a/libc/src/stdlib/calloc.h b/libc/src/stdlib/calloc.h
index bdb025b..a8cf734 100644
--- a/libc/src/stdlib/calloc.h
+++ b/libc/src/stdlib/calloc.h
@@ -6,15 +6,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/macros/config.h"
 #include <stddef.h>
 
 #ifndef LLVM_LIBC_SRC_STDLIB_CALLOC_H
 #define LLVM_LIBC_SRC_STDLIB_CALLOC_H
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void *calloc(size_t num, size_t size);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_CALLOC_H
diff --git a/libc/src/stdlib/div.cpp b/libc/src/stdlib/div.cpp
index ee7c335..766e8ae 100644
--- a/libc/src/stdlib/div.cpp
+++ b/libc/src/stdlib/div.cpp
@@ -9,8 +9,9 @@
 #include "src/stdlib/div.h"
 #include "src/__support/common.h"
 #include "src/__support/integer_operations.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(div_t, div, (int x, int y)) {
   div_t res;
@@ -18,4 +19,4 @@ LLVM_LIBC_FUNCTION(div_t, div, (int x, int y)) {
   return res;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/div.h b/libc/src/stdlib/div.h
index 3a6853f..e76f79b 100644
--- a/libc/src/stdlib/div.h
+++ b/libc/src/stdlib/div.h
@@ -9,12 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_DIV_H
 #define LLVM_LIBC_SRC_STDLIB_DIV_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 div_t div(int x, int y);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_DIV_H
diff --git a/libc/src/stdlib/exit.cpp b/libc/src/stdlib/exit.cpp
index 1afeec5..28a6f8a 100644
--- a/libc/src/stdlib/exit.cpp
+++ b/libc/src/stdlib/exit.cpp
@@ -9,8 +9,9 @@
 #include "src/stdlib/exit.h"
 #include "src/__support/OSUtil/exit.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 extern "C" void __cxa_finalize(void *);
 
@@ -19,4 +20,4 @@ extern "C" void __cxa_finalize(void *);
   internal::exit(status);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/exit.h b/libc/src/stdlib/exit.h
index b135735..1f0153b 100644
--- a/libc/src/stdlib/exit.h
+++ b/libc/src/stdlib/exit.h
@@ -9,12 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_EXIT_H
 #define LLVM_LIBC_SRC_STDLIB_EXIT_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 [[noreturn]] void exit(int status);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_EXIT_H
diff --git a/libc/src/stdlib/exit_handler.cpp b/libc/src/stdlib/exit_handler.cpp
index ed41247..ed0751a 100644
--- a/libc/src/stdlib/exit_handler.cpp
+++ b/libc/src/stdlib/exit_handler.cpp
@@ -8,8 +8,9 @@
 
 #include "src/stdlib/exit_handler.h"
 #include "src/__support/CPP/mutex.h" // lock_guard
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 constinit ExitCallbackList at_quick_exit_callbacks;
 constinit ExitCallbackList atexit_callbacks;
@@ -39,4 +40,4 @@ int add_atexit_unit(ExitCallbackList &callbacks, const AtExitUnit &unit) {
   return -1;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/exit_handler.h b/libc/src/stdlib/exit_handler.h
index 8494c2f..41733b7 100644
--- a/libc/src/stdlib/exit_handler.h
+++ b/libc/src/stdlib/exit_handler.h
@@ -13,9 +13,10 @@
 #include "src/__support/blockstore.h"
 #include "src/__support/common.h"
 #include "src/__support/fixedvector.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/threads/mutex.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 using AtExitCallback = void(void *);
 using StdCAtExitCallback = void(void);
@@ -48,6 +49,6 @@ void call_exit_callbacks(ExitCallbackList &callbacks);
 
 int add_atexit_unit(ExitCallbackList &callbacks, const AtExitUnit &unit);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_EXIT_HANDLER_H
diff --git a/libc/src/stdlib/free.h b/libc/src/stdlib/free.h
index b3970fd..1b250f3 100644
--- a/libc/src/stdlib/free.h
+++ b/libc/src/stdlib/free.h
@@ -6,15 +6,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
 #ifndef LLVM_LIBC_SRC_STDLIB_FREE_H
 #define LLVM_LIBC_SRC_STDLIB_FREE_H
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void free(void *ptr);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_FREE_H
diff --git a/libc/src/stdlib/freelist_malloc.cpp b/libc/src/stdlib/freelist_malloc.cpp
index 684c447..cfffa04 100644
--- a/libc/src/stdlib/freelist_malloc.cpp
+++ b/libc/src/stdlib/freelist_malloc.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/freelist_heap.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/aligned_alloc.h"
 #include "src/stdlib/calloc.h"
 #include "src/stdlib/free.h"
@@ -15,7 +16,7 @@
 
 #include <stddef.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 namespace {
 #ifdef LIBC_FREELIST_MALLOC_SIZE
@@ -47,4 +48,4 @@ LLVM_LIBC_FUNCTION(void *, aligned_alloc, (size_t alignment, size_t size)) {
   return freelist_heap->aligned_allocate(alignment, size);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/getenv.cpp b/libc/src/stdlib/getenv.cpp
index 7a8eb19..6b1bb69 100644
--- a/libc/src/stdlib/getenv.cpp
+++ b/libc/src/stdlib/getenv.cpp
@@ -10,10 +10,11 @@
 #include "config/linux/app.h"
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
 #include <stddef.h> // For size_t.
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(char *, getenv, (const char *name)) {
   char **env_ptr = reinterpret_cast<char **>(LIBC_NAMESPACE::app.env_ptr);
@@ -41,4 +42,4 @@ LLVM_LIBC_FUNCTION(char *, getenv, (const char *name)) {
   return nullptr;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/getenv.h b/libc/src/stdlib/getenv.h
index adb386b..a5d41fe 100644
--- a/libc/src/stdlib/getenv.h
+++ b/libc/src/stdlib/getenv.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_GETENV_H
 #define LLVM_LIBC_SRC_STDLIB_GETENV_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 char *getenv(const char *name);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_GETENV_H
diff --git a/libc/src/stdlib/gpu/abort.cpp b/libc/src/stdlib/gpu/abort.cpp
index f3b052b..fee1986 100644
--- a/libc/src/stdlib/gpu/abort.cpp
+++ b/libc/src/stdlib/gpu/abort.cpp
@@ -8,10 +8,11 @@
 
 #include "src/__support/RPC/rpc_client.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
 #include "src/stdlib/abort.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, abort, ()) {
   // We want to first make sure the server is listening before we abort.
@@ -23,4 +24,4 @@ LLVM_LIBC_FUNCTION(void, abort, ()) {
   gpu::end_program();
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/gpu/free.cpp b/libc/src/stdlib/gpu/free.cpp
index fb5703b..1f0e9ec 100644
--- a/libc/src/stdlib/gpu/free.cpp
+++ b/libc/src/stdlib/gpu/free.cpp
@@ -10,9 +10,10 @@
 
 #include "src/__support/GPU/allocator.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, free, (void *ptr)) { gpu::deallocate(ptr); }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/gpu/malloc.cpp b/libc/src/stdlib/gpu/malloc.cpp
index 9355823..54f2d88 100644
--- a/libc/src/stdlib/gpu/malloc.cpp
+++ b/libc/src/stdlib/gpu/malloc.cpp
@@ -10,11 +10,12 @@
 
 #include "src/__support/GPU/allocator.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void *, malloc, (size_t size)) {
   return gpu::allocate(size);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/labs.cpp b/libc/src/stdlib/labs.cpp
index d9237fa..a8265e4 100644
--- a/libc/src/stdlib/labs.cpp
+++ b/libc/src/stdlib/labs.cpp
@@ -9,9 +9,10 @@
 #include "src/stdlib/labs.h"
 #include "src/__support/common.h"
 #include "src/__support/integer_operations.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long, labs, (long n)) { return integer_abs(n); }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/labs.h b/libc/src/stdlib/labs.h
index b7af538..c15af79 100644
--- a/libc/src/stdlib/labs.h
+++ b/libc/src/stdlib/labs.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_LABS_H
 #define LLVM_LIBC_SRC_STDLIB_LABS_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long labs(long n);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_LABS_H
diff --git a/libc/src/stdlib/ldiv.cpp b/libc/src/stdlib/ldiv.cpp
index 57e2250..94f385f 100644
--- a/libc/src/stdlib/ldiv.cpp
+++ b/libc/src/stdlib/ldiv.cpp
@@ -9,8 +9,9 @@
 #include "src/stdlib/ldiv.h"
 #include "src/__support/common.h"
 #include "src/__support/integer_operations.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(ldiv_t, ldiv, (long x, long y)) {
   ldiv_t res;
@@ -18,4 +19,4 @@ LLVM_LIBC_FUNCTION(ldiv_t, ldiv, (long x, long y)) {
   return res;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/ldiv.h b/libc/src/stdlib/ldiv.h
index 0f0fafa..56b71fd 100644
--- a/libc/src/stdlib/ldiv.h
+++ b/libc/src/stdlib/ldiv.h
@@ -9,12 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_LDIV_H
 #define LLVM_LIBC_SRC_STDLIB_LDIV_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 ldiv_t ldiv(long x, long y);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_LDIV_H
diff --git a/libc/src/stdlib/linux/abort.cpp b/libc/src/stdlib/linux/abort.cpp
index 59feec3..d78ea67 100644
--- a/libc/src/stdlib/linux/abort.cpp
+++ b/libc/src/stdlib/linux/abort.cpp
@@ -7,12 +7,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/signal/raise.h"
 #include "src/stdlib/_Exit.h"
 
 #include "src/stdlib/abort.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, abort, ()) {
   // TODO: When sigprocmask and sigaction land:
@@ -27,4 +28,4 @@ LLVM_LIBC_FUNCTION(void, abort, ()) {
   LIBC_NAMESPACE::_Exit(127);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/llabs.cpp b/libc/src/stdlib/llabs.cpp
index f42c2b8..09636f1 100644
--- a/libc/src/stdlib/llabs.cpp
+++ b/libc/src/stdlib/llabs.cpp
@@ -9,9 +9,10 @@
 #include "src/stdlib/llabs.h"
 #include "src/__support/common.h"
 #include "src/__support/integer_operations.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long long, llabs, (long long n)) { return integer_abs(n); }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/llabs.h b/libc/src/stdlib/llabs.h
index 953fe17..b0cabdd 100644
--- a/libc/src/stdlib/llabs.h
+++ b/libc/src/stdlib/llabs.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_LLABS_H
 #define LLVM_LIBC_SRC_STDLIB_LLABS_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long long llabs(long long n);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_LLABS_H
diff --git a/libc/src/stdlib/lldiv.cpp b/libc/src/stdlib/lldiv.cpp
index ff2fdf8..f55a4f6 100644
--- a/libc/src/stdlib/lldiv.cpp
+++ b/libc/src/stdlib/lldiv.cpp
@@ -9,8 +9,9 @@
 #include "src/stdlib/lldiv.h"
 #include "src/__support/common.h"
 #include "src/__support/integer_operations.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(lldiv_t, lldiv, (long long x, long long y)) {
   lldiv_t res;
@@ -18,4 +19,4 @@ LLVM_LIBC_FUNCTION(lldiv_t, lldiv, (long long x, long long y)) {
   return res;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/lldiv.h b/libc/src/stdlib/lldiv.h
index ee7f4d3..ad688e0 100644
--- a/libc/src/stdlib/lldiv.h
+++ b/libc/src/stdlib/lldiv.h
@@ -8,12 +8,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_LLDIV_H
 #define LLVM_LIBC_SRC_STDLIB_LLDIV_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 lldiv_t lldiv(long long x, long long y);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_LLDIV_H
diff --git a/libc/src/stdlib/malloc.h b/libc/src/stdlib/malloc.h
index 514e2b1..1974f5d 100644
--- a/libc/src/stdlib/malloc.h
+++ b/libc/src/stdlib/malloc.h
@@ -6,15 +6,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
 #ifndef LLVM_LIBC_SRC_STDLIB_MALLOC_H
 #define LLVM_LIBC_SRC_STDLIB_MALLOC_H
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void *malloc(size_t size);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_MALLOC_H
diff --git a/libc/src/stdlib/qsort.cpp b/libc/src/stdlib/qsort.cpp
index f040f37..048e63ab 100644
--- a/libc/src/stdlib/qsort.cpp
+++ b/libc/src/stdlib/qsort.cpp
@@ -8,11 +8,12 @@
 
 #include "src/stdlib/qsort.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/qsort_util.h"
 
 #include <stdint.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, qsort,
                    (void *array, size_t array_size, size_t elem_size,
@@ -24,4 +25,4 @@ LLVM_LIBC_FUNCTION(void, qsort,
                                       array_size, elem_size, c));
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/qsort.h b/libc/src/stdlib/qsort.h
index 5c78481..3898831 100644
--- a/libc/src/stdlib/qsort.h
+++ b/libc/src/stdlib/qsort.h
@@ -9,13 +9,14 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_QSORT_H
 #define LLVM_LIBC_SRC_STDLIB_QSORT_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void qsort(void *array, size_t array_size, size_t elem_size,
            int (*compare)(const void *, const void *));
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_QSORT_H
diff --git a/libc/src/stdlib/qsort_r.cpp b/libc/src/stdlib/qsort_r.cpp
index 7589918..efbe5ad 100644
--- a/libc/src/stdlib/qsort_r.cpp
+++ b/libc/src/stdlib/qsort_r.cpp
@@ -8,11 +8,12 @@
 
 #include "src/stdlib/qsort_r.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/qsort_util.h"
 
 #include <stdint.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, qsort_r,
                    (void *array, size_t array_size, size_t elem_size,
@@ -25,4 +26,4 @@ LLVM_LIBC_FUNCTION(void, qsort_r,
                                       array_size, elem_size, c));
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/qsort_r.h b/libc/src/stdlib/qsort_r.h
index fab0576..574968a 100644
--- a/libc/src/stdlib/qsort_r.h
+++ b/libc/src/stdlib/qsort_r.h
@@ -9,9 +9,10 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_QSORT_R_H
 #define LLVM_LIBC_SRC_STDLIB_QSORT_R_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 // This qsort_r uses the glibc argument ordering instead of the BSD argument
 // ordering (which puts arg before the function pointer). Putting arg after the
@@ -21,6 +22,6 @@ namespace LIBC_NAMESPACE {
 void qsort_r(void *array, size_t array_size, size_t elem_size,
              int (*compare)(const void *, const void *, void *), void *arg);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_QSORT_R_H
diff --git a/libc/src/stdlib/qsort_util.h b/libc/src/stdlib/qsort_util.h
index f4b8094..3a9cc4b 100644
--- a/libc/src/stdlib/qsort_util.h
+++ b/libc/src/stdlib/qsort_util.h
@@ -10,10 +10,12 @@
 #define LLVM_LIBC_SRC_STDLIB_QSORT_UTIL_H
 
 #include "src/__support/macros/attributes.h"
+#include "src/__support/macros/config.h"
 #include <stdint.h>
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE::internal {
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
 
 // A simple quicksort implementation using the Hoare partition scheme.
 
@@ -147,6 +149,7 @@ LIBC_INLINE void quicksort(const Array &array) {
   quicksort(array.make_array(split_index, array.size() - split_index));
 }
 
-} // namespace LIBC_NAMESPACE::internal
+} // namespace internal
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_QSORT_UTIL_H
diff --git a/libc/src/stdlib/quick_exit.cpp b/libc/src/stdlib/quick_exit.cpp
index 38f0a3d..a5abf3e 100644
--- a/libc/src/stdlib/quick_exit.cpp
+++ b/libc/src/stdlib/quick_exit.cpp
@@ -9,10 +9,11 @@
 #include "src/stdlib/quick_exit.h"
 #include "src/__support/OSUtil/exit.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/exit_handler.h"
 
 // extern "C" void __cxa_finalize(void *);
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 extern ExitCallbackList at_quick_exit_callbacks;
 
@@ -21,4 +22,4 @@ extern ExitCallbackList at_quick_exit_callbacks;
   internal::exit(status);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/quick_exit.h b/libc/src/stdlib/quick_exit.h
index 9a3c20c..f41bbaa 100644
--- a/libc/src/stdlib/quick_exit.h
+++ b/libc/src/stdlib/quick_exit.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_QUICK_EXIT_H
 #define LLVM_LIBC_SRC_STDLIB_QUICK_EXIT_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 [[noreturn]] void quick_exit(int status);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_QUICK_EXIT_H
diff --git a/libc/src/stdlib/rand.cpp b/libc/src/stdlib/rand.cpp
index ff3875c..1931727e 100644
--- a/libc/src/stdlib/rand.cpp
+++ b/libc/src/stdlib/rand.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/rand.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/threads/sleep.h"
 #include "src/stdlib/rand_util.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 // An implementation of the xorshift64star pseudo random number generator. This
 // is a good general purpose generator for most non-cryptographics applications.
@@ -29,4 +30,4 @@ LLVM_LIBC_FUNCTION(int, rand, (void)) {
   }
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/rand.h b/libc/src/stdlib/rand.h
index 72bb147..df217b5 100644
--- a/libc/src/stdlib/rand.h
+++ b/libc/src/stdlib/rand.h
@@ -9,12 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_RAND_H
 #define LLVM_LIBC_SRC_STDLIB_RAND_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 int rand(void);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_RAND_H
diff --git a/libc/src/stdlib/rand_util.cpp b/libc/src/stdlib/rand_util.cpp
index ff3478db..c05bdc7 100644
--- a/libc/src/stdlib/rand_util.cpp
+++ b/libc/src/stdlib/rand_util.cpp
@@ -9,11 +9,12 @@
 #include "src/stdlib/rand_util.h"
 #include "src/__support/CPP/atomic.h"
 #include "src/__support/macros/attributes.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 // C standard 7.10p2: If 'rand' is called before 'srand' it is to
 // proceed as if the 'srand' function was called with a value of '1'.
 cpp::Atomic<unsigned long> rand_next = 1;
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/rand_util.h b/libc/src/stdlib/rand_util.h
index 5d7febf..8bf7e58 100644
--- a/libc/src/stdlib/rand_util.h
+++ b/libc/src/stdlib/rand_util.h
@@ -11,14 +11,15 @@
 
 #include "src/__support/CPP/atomic.h"
 #include "src/__support/macros/attributes.h"
+#include "src/__support/macros/config.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 // The ISO C standard does not explicitly require thread-safe behavior for the
 // generic `rand()` function. Some implementations expect it however, so we
 // provide it here.
 extern cpp::Atomic<unsigned long> rand_next;
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_RAND_UTIL_H
diff --git a/libc/src/stdlib/realloc.h b/libc/src/stdlib/realloc.h
index 6e025fa..4d675a6 100644
--- a/libc/src/stdlib/realloc.h
+++ b/libc/src/stdlib/realloc.h
@@ -6,15 +6,16 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/macros/config.h"
 #include <stddef.h>
 
 #ifndef LLVM_LIBC_SRC_STDLIB_REALLOC_H
 #define LLVM_LIBC_SRC_STDLIB_REALLOC_H
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void *realloc(void *ptr, size_t size);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_REALLOC_H
diff --git a/libc/src/stdlib/srand.cpp b/libc/src/stdlib/srand.cpp
index 21166c7..d11c18e 100644
--- a/libc/src/stdlib/srand.cpp
+++ b/libc/src/stdlib/srand.cpp
@@ -8,12 +8,13 @@
 
 #include "src/stdlib/srand.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/rand_util.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(void, srand, (unsigned int seed)) {
   rand_next.store(seed, cpp::MemoryOrder::RELAXED);
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/srand.h b/libc/src/stdlib/srand.h
index 1bcf8de..c9fce46 100644
--- a/libc/src/stdlib/srand.h
+++ b/libc/src/stdlib/srand.h
@@ -9,12 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_SRAND_H
 #define LLVM_LIBC_SRC_STDLIB_SRAND_H
 
+#include "src/__support/macros/config.h"
 #include <stdlib.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 void srand(unsigned int seed);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_SRAND_H
diff --git a/libc/src/stdlib/str_from_util.h b/libc/src/stdlib/str_from_util.h
index 58afa98..7f54bdf 100644
--- a/libc/src/stdlib/str_from_util.h
+++ b/libc/src/stdlib/str_from_util.h
@@ -18,6 +18,7 @@
 #define LLVM_LIBC_SRC_STDLIB_STRFROM_UTIL_H
 
 #include "src/__support/CPP/type_traits.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/stdio/printf_core/converter_atlas.h"
 #include "src/stdio/printf_core/core_structs.h"
@@ -25,7 +26,8 @@
 
 #include <stddef.h>
 
-namespace LIBC_NAMESPACE::internal {
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
 
 template <typename T>
 using storage_type = typename fputil::FPBits<T>::StorageType;
@@ -133,6 +135,7 @@ int strfromfloat_convert(printf_core::Writer *writer,
   return -1;
 }
 
-} // namespace LIBC_NAMESPACE::internal
+} // namespace internal
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRFROM_UTIL_H
diff --git a/libc/src/stdlib/strfromd.cpp b/libc/src/stdlib/strfromd.cpp
index 329f6fd..4c51e4c 100644
--- a/libc/src/stdlib/strfromd.cpp
+++ b/libc/src/stdlib/strfromd.cpp
@@ -7,9 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/stdlib/strfromd.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/str_from_util.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, strfromd,
                    (char *__restrict s, size_t n, const char *__restrict format,
@@ -36,4 +37,4 @@ LLVM_LIBC_FUNCTION(int, strfromd,
   return writer.get_chars_written();
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strfromd.h b/libc/src/stdlib/strfromd.h
index d2c3fef..8a68ff5 100644
--- a/libc/src/stdlib/strfromd.h
+++ b/libc/src/stdlib/strfromd.h
@@ -9,13 +9,14 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRFROMD_H
 #define LLVM_LIBC_SRC_STDLIB_STRFROMD_H
 
+#include "src/__support/macros/config.h"
 #include <stddef.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 int strfromd(char *__restrict s, size_t n, const char *__restrict format,
              double fp);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRFROMD_H
diff --git a/libc/src/stdlib/strfromf.cpp b/libc/src/stdlib/strfromf.cpp
index 80e1d74..ea98a69 100644
--- a/libc/src/stdlib/strfromf.cpp
+++ b/libc/src/stdlib/strfromf.cpp
@@ -7,9 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/stdlib/strfromf.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/str_from_util.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, strfromf,
                    (char *__restrict s, size_t n, const char *__restrict format,
@@ -36,4 +37,4 @@ LLVM_LIBC_FUNCTION(int, strfromf,
   return writer.get_chars_written();
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strfromf.h b/libc/src/stdlib/strfromf.h
index 492c2c3..e65e6b3 100644
--- a/libc/src/stdlib/strfromf.h
+++ b/libc/src/stdlib/strfromf.h
@@ -9,13 +9,14 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRFROMF_H
 #define LLVM_LIBC_SRC_STDLIB_STRFROMF_H
 
+#include "src/__support/macros/config.h"
 #include <stddef.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 int strfromf(char *__restrict s, size_t n, const char *__restrict format,
              float fp);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRFROMF_H
diff --git a/libc/src/stdlib/strfroml.cpp b/libc/src/stdlib/strfroml.cpp
index f0bc935..d5bee76 100644
--- a/libc/src/stdlib/strfroml.cpp
+++ b/libc/src/stdlib/strfroml.cpp
@@ -7,9 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/stdlib/strfroml.h"
+#include "src/__support/macros/config.h"
 #include "src/stdlib/str_from_util.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(int, strfroml,
                    (char *__restrict s, size_t n, const char *__restrict format,
@@ -41,4 +42,4 @@ LLVM_LIBC_FUNCTION(int, strfroml,
   return writer.get_chars_written();
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strfroml.h b/libc/src/stdlib/strfroml.h
index e99d035..1bff12e 100644
--- a/libc/src/stdlib/strfroml.h
+++ b/libc/src/stdlib/strfroml.h
@@ -9,13 +9,14 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRFROML_H
 #define LLVM_LIBC_SRC_STDLIB_STRFROML_H
 
+#include "src/__support/macros/config.h"
 #include <stddef.h>
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 int strfroml(char *__restrict s, size_t n, const char *__restrict format,
              long double fp);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRFROML_H
diff --git a/libc/src/stdlib/strtod.cpp b/libc/src/stdlib/strtod.cpp
index 461f7fe..2c68191 100644
--- a/libc/src/stdlib/strtod.cpp
+++ b/libc/src/stdlib/strtod.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtod.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_float.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(double, strtod,
                    (const char *__restrict str, char **__restrict str_end)) {
@@ -25,4 +26,4 @@ LLVM_LIBC_FUNCTION(double, strtod,
   return result.value;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtod.h b/libc/src/stdlib/strtod.h
index 5efad84..1a32e38 100644
--- a/libc/src/stdlib/strtod.h
+++ b/libc/src/stdlib/strtod.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOD_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOD_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 double strtod(const char *__restrict str, char **__restrict str_end);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOD_H
diff --git a/libc/src/stdlib/strtof.cpp b/libc/src/stdlib/strtof.cpp
index 554d096..351bf64 100644
--- a/libc/src/stdlib/strtof.cpp
+++ b/libc/src/stdlib/strtof.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtof.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_float.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(float, strtof,
                    (const char *__restrict str, char **__restrict str_end)) {
@@ -25,4 +26,4 @@ LLVM_LIBC_FUNCTION(float, strtof,
   return result.value;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtof.h b/libc/src/stdlib/strtof.h
index d800b22..2e7645f 100644
--- a/libc/src/stdlib/strtof.h
+++ b/libc/src/stdlib/strtof.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOF_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOF_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 float strtof(const char *__restrict str, char **__restrict str_end);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOF_H
diff --git a/libc/src/stdlib/strtol.cpp b/libc/src/stdlib/strtol.cpp
index e9bedf2..77f8712 100644
--- a/libc/src/stdlib/strtol.cpp
+++ b/libc/src/stdlib/strtol.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtol.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long, strtol,
                    (const char *__restrict str, char **__restrict str_end,
@@ -26,4 +27,4 @@ LLVM_LIBC_FUNCTION(long, strtol,
   return result;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtol.h b/libc/src/stdlib/strtol.h
index c46c650..54779d4 100644
--- a/libc/src/stdlib/strtol.h
+++ b/libc/src/stdlib/strtol.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOL_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOL_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long strtol(const char *__restrict str, char **__restrict str_end, int base);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOL_H
diff --git a/libc/src/stdlib/strtold.cpp b/libc/src/stdlib/strtold.cpp
index 9c3e1db..88d29c9 100644
--- a/libc/src/stdlib/strtold.cpp
+++ b/libc/src/stdlib/strtold.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtold.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_float.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long double, strtold,
                    (const char *__restrict str, char **__restrict str_end)) {
@@ -25,4 +26,4 @@ LLVM_LIBC_FUNCTION(long double, strtold,
   return result.value;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtold.h b/libc/src/stdlib/strtold.h
index 6a0b5d4..4b663ca 100644
--- a/libc/src/stdlib/strtold.h
+++ b/libc/src/stdlib/strtold.h
@@ -9,10 +9,12 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOLD_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOLD_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long double strtold(const char *__restrict str, char **__restrict str_end);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOLD_H
diff --git a/libc/src/stdlib/strtoll.cpp b/libc/src/stdlib/strtoll.cpp
index 99e8205..8d1b3ef 100644
--- a/libc/src/stdlib/strtoll.cpp
+++ b/libc/src/stdlib/strtoll.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtoll.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(long long, strtoll,
                    (const char *__restrict str, char **__restrict str_end,
@@ -26,4 +27,4 @@ LLVM_LIBC_FUNCTION(long long, strtoll,
   return result;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtoll.h b/libc/src/stdlib/strtoll.h
index d699785..399c20b 100644
--- a/libc/src/stdlib/strtoll.h
+++ b/libc/src/stdlib/strtoll.h
@@ -9,11 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOLL_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOLL_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 long long strtoll(const char *__restrict str, char **__restrict str_end,
                   int base);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOLL_H
diff --git a/libc/src/stdlib/strtoul.cpp b/libc/src/stdlib/strtoul.cpp
index f50ed7e..1d83231 100644
--- a/libc/src/stdlib/strtoul.cpp
+++ b/libc/src/stdlib/strtoul.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtoul.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(unsigned long, strtoul,
                    (const char *__restrict str, char **__restrict str_end,
@@ -26,4 +27,4 @@ LLVM_LIBC_FUNCTION(unsigned long, strtoul,
   return result;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtoul.h b/libc/src/stdlib/strtoul.h
index af83992..ca1911a 100644
--- a/libc/src/stdlib/strtoul.h
+++ b/libc/src/stdlib/strtoul.h
@@ -9,11 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOUL_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOUL_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 unsigned long strtoul(const char *__restrict str, char **__restrict str_end,
                       int base);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOUL_H
diff --git a/libc/src/stdlib/strtoull.cpp b/libc/src/stdlib/strtoull.cpp
index de3a0d0..dba2261 100644
--- a/libc/src/stdlib/strtoull.cpp
+++ b/libc/src/stdlib/strtoull.cpp
@@ -8,10 +8,11 @@
 
 #include "src/stdlib/strtoull.h"
 #include "src/__support/common.h"
+#include "src/__support/macros/config.h"
 #include "src/__support/str_to_integer.h"
 #include "src/errno/libc_errno.h"
 
-namespace LIBC_NAMESPACE {
+namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(unsigned long long, strtoull,
                    (const char *__restrict str, char **__restrict str_end,
@@ -26,4 +27,4 @@ LLVM_LIBC_FUNCTION(unsigned long long, strtoull,
   return result;
 }
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdlib/strtoull.h b/libc/src/stdlib/strtoull.h
index 47ed101..58801e5 100644
--- a/libc/src/stdlib/strtoull.h
+++ b/libc/src/stdlib/strtoull.h
@@ -9,11 +9,13 @@
 #ifndef LLVM_LIBC_SRC_STDLIB_STRTOULL_H
 #define LLVM_LIBC_SRC_STDLIB_STRTOULL_H
 
-namespace LIBC_NAMESPACE {
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
 
 unsigned long long strtoull(const char *__restrict str,
                             char **__restrict str_end, int base);
 
-} // namespace LIBC_NAMESPACE
+} // namespace LIBC_NAMESPACE_DECL
 
 #endif // LLVM_LIBC_SRC_STDLIB_STRTOULL_H