[libc++] Make sure that all headers can be included with modules enabled

This commit ensures that we can include all libc++ headers with modules
enabled. It adds a test to ensure that this doesn't regress, which is
necessary because our modules CI job does not build in all Standard modes.

Differential Revision: https://reviews.llvm.org/D125331

6 files changed, 12 insertions, 4 deletions

diff --git a/libcxx/include/__filesystem/u8path.h b/libcxx/include/__filesystem/u8path.h
index ee25521..d35faa1 100644
--- a/libcxx/include/__filesystem/u8path.h
+++ b/libcxx/include/__filesystem/u8path.h
@@ -10,11 +10,19 @@
 #ifndef _LIBCPP___FILESYSTEM_U8PATH_H
 #define _LIBCPP___FILESYSTEM_U8PATH_H
 
+#include <__algorithm/unwrap_iter.h>
 #include <__availability>
 #include <__config>
 #include <__filesystem/path.h>
+#include <string>
 #include <type_traits>
 
+// Only required on Windows for __widen_from_utf8, and included conservatively
+// because it requires support for localization.
+#if defined(_LIBCPP_WIN32API)
+# include <locale>
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
diff --git a/libcxx/include/barrier b/libcxx/include/barrier
index 36ea6f58..f03c089 100644
--- a/libcxx/include/barrier
+++ b/libcxx/include/barrier
@@ -50,6 +50,7 @@ namespace std
 #include <__config>
 #include <__thread/timed_backoff_policy.h>
 #include <atomic>
+#include <limits>
 #ifndef _LIBCPP_HAS_NO_TREE_BARRIER
 # include <memory>
 #endif
diff --git a/libcxx/include/latch b/libcxx/include/latch
index 21abbad..8593675 100644
--- a/libcxx/include/latch
+++ b/libcxx/include/latch
@@ -44,6 +44,7 @@ namespace std
 #include <__availability>
 #include <__config>
 #include <atomic>
+#include <limits>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index 132793f..6a771ea 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -3,7 +3,6 @@
 // include cycle.
 module std_config [system] [extern_c] {
   header "__config"
-  header "__config_site"
   export *
 }
 
@@ -370,7 +369,6 @@ module std [system] {
     export *
   }
   module barrier {
-    requires cplusplus14
     header "barrier"
     export *
   }
@@ -698,7 +696,6 @@ module std [system] {
     }
   }
   module latch {
-    requires cplusplus14
     header "latch"
     export *
   }
@@ -906,7 +903,6 @@ module std [system] {
     export *
   }
   module semaphore {
-    requires cplusplus14
     header "semaphore"
     export *
   }
diff --git a/libcxx/include/semaphore b/libcxx/include/semaphore
index ce1fa69..228cf77 100644
--- a/libcxx/include/semaphore
+++ b/libcxx/include/semaphore
@@ -52,6 +52,7 @@ using binary_semaphore = counting_semaphore<1>;
 #include <__thread/timed_backoff_policy.h>
 #include <__threading_support>
 #include <atomic>
+#include <limits>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/span b/libcxx/include/span
index 98ecfd4..15564d8 100644
--- a/libcxx/include/span
+++ b/libcxx/include/span
@@ -138,6 +138,7 @@ template<class R>
 #include <__ranges/enable_borrowed_range.h>
 #include <__ranges/enable_view.h>
 #include <__ranges/size.h>
+#include <__utility/forward.h>
 #include <array>        // for array
 #include <cstddef>      // for byte
 #include <iterator>     // for iterators