libstdc++: Mark headers that must be hosted as such [PR103626]

PR libstdc++/103626 - _GLIBCXX_HOSTED should respect -ffreestanding

Co-authored-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/103626
	* include/Makefile.am: Add new header.
	* include/Makefile.in: Regenerate.
	* include/bits/requires_hosted.h: New header.
	* include/experimental/algorithm: Include
	<bits/requires_hosted.h>.
	* include/experimental/any: Likewise.
	* include/experimental/array: Likewise.
	* include/experimental/buffer: Likewise.
	* include/experimental/chrono: Likewise.
	* include/experimental/deque: Likewise.
	* include/experimental/executor: Likewise.
	* include/experimental/filesystem: Likewise.
	* include/experimental/forward_list: Likewise.
	* include/experimental/functional: Likewise.
	* include/experimental/internet: Likewise.
	* include/experimental/io_context: Likewise.
	* include/experimental/iterator: Likewise.
	* include/experimental/list: Likewise.
	* include/experimental/map: Likewise.
	* include/experimental/memory: Likewise.
	* include/experimental/memory_resource: Likewise.
	* include/experimental/net: Likewise.
	* include/experimental/netfwd: Likewise.
	* include/experimental/numeric: Likewise.
	* include/experimental/optional: Likewise.
	* include/experimental/propagate_const: Likewise.
	* include/experimental/random: Likewise.
	* include/experimental/ratio: Likewise.
	* include/experimental/regex: Likewise.
	* include/experimental/scope: Likewise.
	* include/experimental/set: Likewise.
	* include/experimental/simd: Likewise.
	* include/experimental/socket: Likewise.
	* include/experimental/source_location: Likewise.
	* include/experimental/string: Likewise.
	* include/experimental/string_view: Likewise.
	* include/experimental/system_error: Likewise.
	* include/experimental/timer: Likewise.
	* include/experimental/tuple: Likewise.
	* include/experimental/unordered_map: Likewise.
	* include/experimental/unordered_set: Likewise.
	* include/experimental/utility: Likewise.
	* include/experimental/vector: Likewise.
	* include/std/barrier: Likewise.
	* include/std/chrono: Likewise.
	* include/std/condition_variable: Likewise.
	* include/std/deque: Likewise.
	* include/std/execution: Likewise.
	* include/std/filesystem: Likewise.
	* include/std/forward_list: Likewise.
	* include/std/fstream: Likewise.
	* include/std/future: Likewise.
	* include/std/iomanip: Likewise.
	* include/std/ios: Likewise.
	* include/std/iosfwd: Likewise.
	* include/std/iostream: Likewise.
	* include/std/istream: Likewise.
	* include/std/latch: Likewise.
	* include/std/list: Likewise.
	* include/std/locale: Likewise.
	* include/std/map: Likewise.
	* include/std/memory_resource: Likewise.
	* include/std/mutex: Likewise.
	* include/std/ostream: Likewise.
	* include/std/queue: Likewise.
	* include/std/random: Likewise.
	* include/std/regex: Likewise.
	* include/std/semaphore: Likewise.
	* include/std/set: Likewise.
	* include/std/shared_mutex: Likewise.
	* include/std/spanstream: Likewise.
	* include/std/sstream: Likewise.
	* include/std/stack: Likewise.
	* include/std/stacktrace: Likewise.
	* include/std/stop_token: Likewise.
	* include/std/streambuf: Likewise.
	* include/std/string: Likewise.
	* include/std/syncstream: Likewise.
	* include/std/system_error: Likewise.
	* include/std/thread: Likewise.
	* include/std/unordered_map: Likewise.
	* include/std/unordered_set: Likewise.
	* include/std/valarray: Likewise.
	* include/std/vector: Likewise.
	* include/tr1/array: Likewise.
	* include/tr1/ccomplex: Likewise.
	* include/tr1/cctype: Likewise.
	* include/tr1/cfenv: Likewise.
	* include/tr1/cfloat: Likewise.
	* include/tr1/cinttypes: Likewise.
	* include/tr1/climits: Likewise.
	* include/tr1/cmath: Likewise.
	* include/tr1/complex: Likewise.
	* include/tr1/complex.h: Likewise.
	* include/tr1/cstdarg: Likewise.
	* include/tr1/cstdbool: Likewise.
	* include/tr1/cstdint: Likewise.
	* include/tr1/cstdio: Likewise.
	* include/tr1/cstdlib: Likewise.
	* include/tr1/ctgmath: Likewise.
	* include/tr1/ctime: Likewise.
	* include/tr1/ctype.h: Likewise.
	* include/tr1/cwchar: Likewise.
	* include/tr1/cwctype: Likewise.
	* include/tr1/fenv.h: Likewise.
	* include/tr1/float.h: Likewise.
	* include/tr1/functional: Likewise.
	* include/tr1/inttypes.h: Likewise.
	* include/tr1/limits.h: Likewise.
	* include/tr1/math.h: Likewise.
	* include/tr1/memory: Likewise.
	* include/tr1/random: Likewise.
	* include/tr1/regex: Likewise.
	* include/tr1/stdarg.h: Likewise.
	* include/tr1/stdbool.h: Likewise.
	* include/tr1/stdint.h: Likewise.
	* include/tr1/stdio.h: Likewise.
	* include/tr1/stdlib.h: Likewise.
	* include/tr1/tgmath.h: Likewise.
	* include/tr1/tuple: Likewise.
	* include/tr1/type_traits: Likewise.
	* include/tr1/unordered_map: Likewise.
	* include/tr1/unordered_set: Likewise.
	* include/tr1/utility: Likewise.
	* include/tr1/wchar.h: Likewise.
	* include/tr1/wctype.h: Likewise.
	* include/c_global/cmath: Likewise.
	* include/ext/algorithm: Include <bits/requires_hosted.h>.
	* include/ext/bitmap_allocator.h: Likewise.
	* include/ext/cmath: Likewise.
	* include/ext/codecvt_specializations.h: Likewise.
	* include/ext/debug_allocator.h: Likewise.
	* include/ext/enc_filebuf.h: Likewise.
	* include/ext/extptr_allocator.h: Likewise.
	* include/ext/functional: Likewise.
	* include/ext/malloc_allocator.h: Likewise.
	* include/ext/memory: Likewise.
	* include/ext/mt_allocator.h: Likewise.
	* include/ext/new_allocator.h: Likewise.
	* include/ext/numeric: Likewise.
	* include/ext/pod_char_traits.h: Likewise.
	* include/ext/pool_allocator.h: Likewise.
	* include/ext/random: Likewise.
	* include/ext/random.tcc: Likewise.
	* include/ext/rb_tree: Likewise.
	* include/ext/rc_string_base.h: Likewise.
	* include/ext/rope: Likewise.
	* include/ext/ropeimpl.h: Likewise.
	* include/ext/slist: Likewise.
	* include/ext/sso_string_base.h: Likewise.
	* include/ext/stdio_filebuf.h: Likewise.
	* include/ext/stdio_sync_filebuf.h: Likewise.
	* include/ext/string_conversions.h: Likewise.
	* include/ext/throw_allocator.h: Likewise.
	* include/ext/vstring.h: Likewise.
	* include/ext/vstring.tcc: Likewise.
	* include/ext/vstring_fwd.h: Likewise.
	* include/ext/vstring_util.h: Likewise.
	* include/std/charconv: Likewise.
	(__cpp_lib_to_chars): Do not define for freestanding.
	* include/std/version: Adjust which macros get defined in
	freestanding.
	* include/ext/pointer.h [!_GLIBCXX_HOSTED]: Omit iostream
	functionality from freestanding.
	* include/std/algorithm [!_GLIBCXX_HOSTED]: Omit PSTL algos.
	* include/std/memory [!_GLIBCXX_HOSTED]: Omit
	<bits/stl_tempbuf.h> in freestanding
	* include/bits/algorithmfwd.h [!_GLIBCXX_HOSTED]: Omit leftover
	random_shuffle and stable_partition definition.
	* include/bits/stl_algo.h [!_GLIBCXX_HOSTED]: Omit
	random_shuffle and stable_partition from freestanding.
	* include/bits/ranges_algo.h [!_GLIBCXX_HOSTED]: Omit
	stable_partition from freestanding.
	* include/bits/concept_check.h: Remove needless HOSTED check.
	* include/std/iterator: Include <bits/ranges_base.h>.
	* include/std/numeric (__cpp_lib_parallel_algorithms): Do not
	define for freestanding.
	* include/std/functional (__cpp_lib_boyer_moore_searcher):
	Likewise.
	* testsuite/lib/prune.exp: Match error for hosted-only libstdc++
	tests.

48 files changed, 145 insertions, 56 deletions

diff --git a/libstdc++-v3/include/std/algorithm b/libstdc++-v3/include/std/algorithm
index e2cfd7c..4b39bfc 100644
--- a/libstdc++-v3/include/std/algorithm
+++ b/libstdc++-v3/include/std/algorithm
@@ -63,7 +63,7 @@
 # include <bits/ranges_algo.h>
 #endif
 
-#if __cplusplus > 201402L
+#if __cplusplus > 201402L && _GLIBCXX_HOSTED
 // Parallel STL algorithms
 # if _PSTL_EXECUTION_POLICIES_DEFINED
 // If <execution> has already been included, pull in implementations
@@ -76,7 +76,7 @@
 
 // Feature test macro for parallel algorithms
 # define __cpp_lib_parallel_algorithm 201603L
-#endif // C++17
+#endif // C++17 && HOSTED
 
 #ifdef _GLIBCXX_PARALLEL
 # include <parallel/algorithm>
diff --git a/libstdc++-v3/include/std/barrier b/libstdc++-v3/include/std/barrier
index 997e0a8..ab6dd8b 100644
--- a/libstdc++-v3/include/std/barrier
+++ b/libstdc++-v3/include/std/barrier
@@ -40,6 +40,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // threading primitive
+
 #if __cplusplus > 201703L
 #include <bits/atomic_base.h>
 #if __cpp_lib_atomic_wait && __cpp_aligned_new
diff --git a/libstdc++-v3/include/std/charconv b/libstdc++-v3/include/std/charconv
index 533320e..64d0584 100644
--- a/libstdc++-v3/include/std/charconv
+++ b/libstdc++-v3/include/std/charconv
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // for error codes
+
 // As an extension we support <charconv> in C++14, but this header should not
 // be included by any other library headers in C++14 mode. This ensures that
 // the names defined in this header are not added to namespace std unless a
@@ -44,7 +46,7 @@
 #include <ext/numeric_traits.h>
 
 #if _GLIBCXX_FLOAT_IS_IEEE_BINARY32 && _GLIBCXX_DOUBLE_IS_IEEE_BINARY64 \
-    && __SIZE_WIDTH__ >= 32
+    && __SIZE_WIDTH__ >= 32 && _GLIBCXX_HOSTED
 # define __cpp_lib_to_chars 201611L
 #endif
 
diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono
index 3732a40..c0c3a67 100644
--- a/libstdc++-v3/include/std/chrono
+++ b/libstdc++-v3/include/std/chrono
@@ -32,6 +32,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // for <ctime> and clocks
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/condition_variable b/libstdc++-v3/include/std/condition_variable
index 06c4ff9..b885e1b 100644
--- a/libstdc++-v3/include/std/condition_variable
+++ b/libstdc++-v3/include/std/condition_variable
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // threading primitive
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/deque b/libstdc++-v3/include/std/deque
index abdc2e0..0b692f1 100644
--- a/libstdc++-v3/include/std/deque
+++ b/libstdc++-v3/include/std/deque
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers are hosted only
+
 #include <bits/stl_algobase.h>
 #include <bits/allocator.h>
 #include <bits/stl_construct.h>
diff --git a/libstdc++-v3/include/std/execution b/libstdc++-v3/include/std/execution
index e933a1a..17f62a2 100644
--- a/libstdc++-v3/include/std/execution
+++ b/libstdc++-v3/include/std/execution
@@ -27,6 +27,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // execution policies are hosted only
+
 #if __cplusplus >= 201703L
 # include <bits/c++config.h>
 # include <pstl/glue_execution_defs.h>
diff --git a/libstdc++-v3/include/std/filesystem b/libstdc++-v3/include/std/filesystem
index dd112a2..36d71dd 100644
--- a/libstdc++-v3/include/std/filesystem
+++ b/libstdc++-v3/include/std/filesystem
@@ -32,6 +32,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h>
+
 #if __cplusplus >= 201703L
 
 /**
diff --git a/libstdc++-v3/include/std/forward_list b/libstdc++-v3/include/std/forward_list
index fe99e5e..5d8052c 100644
--- a/libstdc++-v3/include/std/forward_list
+++ b/libstdc++-v3/include/std/forward_list
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/fstream b/libstdc++-v3/include/std/fstream
index e62a1ad..c434664 100644
--- a/libstdc++-v3/include/std/fstream
+++ b/libstdc++-v3/include/std/fstream
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <istream>
 #include <ostream>
 #include <bits/codecvt.h>
diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 5235ef2..adf9cb1 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -1105,7 +1105,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     }
 
   // Searchers
-#define __cpp_lib_boyer_moore_searcher 201603L
 
   template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
     class default_searcher
@@ -1138,6 +1137,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 
 #if _GLIBCXX_HOSTED
+#define __cpp_lib_boyer_moore_searcher 201603L
+
   template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
     struct __boyer_moore_map_base
     {
diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future
index cf08c15..8c968fe 100644
--- a/libstdc++-v3/include/std/future
+++ b/libstdc++-v3/include/std/future
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/iomanip b/libstdc++-v3/include/std/iomanip
index 5371681..f73519d 100644
--- a/libstdc++-v3/include/std/iomanip
+++ b/libstdc++-v3/include/std/iomanip
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <bits/c++config.h>
 #include <iosfwd>
 #include <bits/ios_base.h>
diff --git a/libstdc++-v3/include/std/ios b/libstdc++-v3/include/std/ios
index 50a66cd..c759986 100644
--- a/libstdc++-v3/include/std/ios
+++ b/libstdc++-v3/include/std/ios
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <iosfwd>
 #include <exception> 		// For ios_base::failure
 #include <bits/char_traits.h> 	// For char_traits, streamoff, streamsize, fpos
diff --git a/libstdc++-v3/include/std/iosfwd b/libstdc++-v3/include/std/iosfwd
index ddf0c95..7f156f8 100644
--- a/libstdc++-v3/include/std/iosfwd
+++ b/libstdc++-v3/include/std/iosfwd
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <bits/c++config.h>
 #include <bits/stringfwd.h> 	// For string forward declarations.
 #include <bits/postypes.h>
diff --git a/libstdc++-v3/include/std/iostream b/libstdc++-v3/include/std/iostream
index d705913..685d29a 100644
--- a/libstdc++-v3/include/std/iostream
+++ b/libstdc++-v3/include/std/iostream
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <bits/c++config.h>
 #include <ostream>
 #include <istream>
diff --git a/libstdc++-v3/include/std/istream b/libstdc++-v3/include/std/istream
index 416ef55..58716ce 100644
--- a/libstdc++-v3/include/std/istream
+++ b/libstdc++-v3/include/std/istream
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <ios>
 #include <ostream>
 
diff --git a/libstdc++-v3/include/std/iterator b/libstdc++-v3/include/std/iterator
index fb2a47c..8ee8327 100644
--- a/libstdc++-v3/include/std/iterator
+++ b/libstdc++-v3/include/std/iterator
@@ -71,4 +71,8 @@
 # define __cpp_lib_null_iterators 201304L
 #endif
 
+#if __cplusplus >= 202002L
+#include <bits/ranges_base.h> // ranges::distance, ranges::next, ranges::prev
+#endif
+
 #endif /* _GLIBCXX_ITERATOR */
diff --git a/libstdc++-v3/include/std/latch b/libstdc++-v3/include/std/latch
index 7ae9022..0442f09 100644
--- a/libstdc++-v3/include/std/latch
+++ b/libstdc++-v3/include/std/latch
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus > 201703L
 
 #include <bits/atomic_base.h>
diff --git a/libstdc++-v3/include/std/list b/libstdc++-v3/include/std/list
index 9151e98..ec174ed 100644
--- a/libstdc++-v3/include/std/list
+++ b/libstdc++-v3/include/std/list
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #include <bits/stl_algobase.h>
 #include <bits/allocator.h>
 #include <bits/range_access.h>
diff --git a/libstdc++-v3/include/std/locale b/libstdc++-v3/include/std/locale
index ae83586..abfed05 100644
--- a/libstdc++-v3/include/std/locale
+++ b/libstdc++-v3/include/std/locale
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // locales
+
 #include <bits/localefwd.h>
 #include <bits/locale_classes.h>
 #include <bits/locale_facets.h>
diff --git a/libstdc++-v3/include/std/map b/libstdc++-v3/include/std/map
index ce07f29..c973a8e 100644
--- a/libstdc++-v3/include/std/map
+++ b/libstdc++-v3/include/std/map
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #include <bits/stl_tree.h>
 #include <bits/stl_map.h>
 #include <bits/stl_multimap.h>
diff --git a/libstdc++-v3/include/std/memory b/libstdc++-v3/include/std/memory
index 3eff121..4336724 100644
--- a/libstdc++-v3/include/std/memory
+++ b/libstdc++-v3/include/std/memory
@@ -63,10 +63,10 @@
 #include <bits/memoryfwd.h>
 #if _GLIBCXX_HOSTED
 # include <bits/allocator.h>
+# include <bits/stl_tempbuf.h>
 #endif
 #include <bits/stl_construct.h>
 #include <bits/stl_uninitialized.h>
-#include <bits/stl_tempbuf.h>
 #include <bits/stl_raw_storage_iter.h>
 
 #if __cplusplus >= 201103L
diff --git a/libstdc++-v3/include/std/memory_resource b/libstdc++-v3/include/std/memory_resource
index 19c9225..323956e 100644
--- a/libstdc++-v3/include/std/memory_resource
+++ b/libstdc++-v3/include/std/memory_resource
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // polymorphic allocation
+
 #if __cplusplus >= 201703L
 
 #include <bits/memory_resource.h>
diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index b9590bb..b310c15 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/numeric b/libstdc++-v3/include/std/numeric
index 60a99d1..0f1f26c 100644
--- a/libstdc++-v3/include/std/numeric
+++ b/libstdc++-v3/include/std/numeric
@@ -729,7 +729,7 @@ namespace __detail
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L && _GLIBCXX_HOSTED
 // Parallel STL algorithms
 # if _PSTL_EXECUTION_POLICIES_DEFINED
 // If <execution> has already been included, pull in implementations
diff --git a/libstdc++-v3/include/std/ostream b/libstdc++-v3/include/std/ostream
index 291ea40..674decf 100644
--- a/libstdc++-v3/include/std/ostream
+++ b/libstdc++-v3/include/std/ostream
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <ios>
 #include <bits/ostream_insert.h>
 
diff --git a/libstdc++-v3/include/std/queue b/libstdc++-v3/include/std/queue
index db81ef1..7c4952f 100644
--- a/libstdc++-v3/include/std/queue
+++ b/libstdc++-v3/include/std/queue
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #include <deque>
 #include <vector>
 #include <bits/stl_heap.h>
diff --git a/libstdc++-v3/include/std/random b/libstdc++-v3/include/std/random
index 89a2f16..66757f7 100644
--- a/libstdc++-v3/include/std/random
+++ b/libstdc++-v3/include/std/random
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // OS-dependent random
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/regex b/libstdc++-v3/include/std/regex
index 491bced..aa50c7e 100644
--- a/libstdc++-v3/include/std/regex
+++ b/libstdc++-v3/include/std/regex
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // string and container heavy
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/semaphore b/libstdc++-v3/include/std/semaphore
index 8a31c6d..72d68dd 100644
--- a/libstdc++-v3/include/std/semaphore
+++ b/libstdc++-v3/include/std/semaphore
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus > 201703L
 #include <bits/semaphore_base.h>
 
diff --git a/libstdc++-v3/include/std/set b/libstdc++-v3/include/std/set
index 551c777..4cbcba1 100644
--- a/libstdc++-v3/include/std/set
+++ b/libstdc++-v3/include/std/set
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #include <bits/stl_tree.h>
 #include <bits/stl_set.h>
 #include <bits/stl_multiset.h>
diff --git a/libstdc++-v3/include/std/shared_mutex b/libstdc++-v3/include/std/shared_mutex
index 817a958..cf74b32 100644
--- a/libstdc++-v3/include/std/shared_mutex
+++ b/libstdc++-v3/include/std/shared_mutex
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus >= 201402L
 
 #include <bits/chrono.h>
diff --git a/libstdc++-v3/include/std/spanstream b/libstdc++-v3/include/std/spanstream
index 5855b28..6abf013 100644
--- a/libstdc++-v3/include/std/spanstream
+++ b/libstdc++-v3/include/std/spanstream
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #if __cplusplus > 202002L
 #include <span>
 #include <streambuf>
diff --git a/libstdc++-v3/include/std/sstream b/libstdc++-v3/include/std/sstream
index bc7d636..7305bdb 100644
--- a/libstdc++-v3/include/std/sstream
+++ b/libstdc++-v3/include/std/sstream
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostream
+
 #include <istream>
 #include <ostream>
 #include <bits/alloc_traits.h> // allocator_traits, __allocator_like
diff --git a/libstdc++-v3/include/std/stack b/libstdc++-v3/include/std/stack
index fc14e2e..98d2123 100644
--- a/libstdc++-v3/include/std/stack
+++ b/libstdc++-v3/include/std/stack
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #include <deque>
 #include <bits/stl_stack.h>
 
diff --git a/libstdc++-v3/include/std/stacktrace b/libstdc++-v3/include/std/stacktrace
index 39472d7..e7cbbee 100644
--- a/libstdc++-v3/include/std/stacktrace
+++ b/libstdc++-v3/include/std/stacktrace
@@ -26,6 +26,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // std::string bound
+
 #include <bits/c++config.h>
 
 #if __cplusplus > 202002L && _GLIBCXX_HAVE_STACKTRACE
diff --git a/libstdc++-v3/include/std/stop_token b/libstdc++-v3/include/std/stop_token
index 07d4fda..f196834 100644
--- a/libstdc++-v3/include/std/stop_token
+++ b/libstdc++-v3/include/std/stop_token
@@ -29,6 +29,8 @@
 #ifndef _GLIBCXX_STOP_TOKEN
 #define _GLIBCXX_STOP_TOKEN
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus > 201703L
 
 #include <atomic>
diff --git a/libstdc++-v3/include/std/streambuf b/libstdc++-v3/include/std/streambuf
index 888611d..d8893df 100644
--- a/libstdc++-v3/include/std/streambuf
+++ b/libstdc++-v3/include/std/streambuf
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <bits/c++config.h>
 #include <iosfwd>
 #include <bits/localefwd.h>
diff --git a/libstdc++-v3/include/std/string b/libstdc++-v3/include/std/string
index 62ecdb3..41e6e2c 100644
--- a/libstdc++-v3/include/std/string
+++ b/libstdc++-v3/include/std/string
@@ -35,6 +35,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #include <bits/c++config.h>
 #include <bits/stringfwd.h>
 #include <bits/char_traits.h>
diff --git a/libstdc++-v3/include/std/syncstream b/libstdc++-v3/include/std/syncstream
index 7a4f731..838cec5 100644
--- a/libstdc++-v3/include/std/syncstream
+++ b/libstdc++-v3/include/std/syncstream
@@ -38,6 +38,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // iostreams
+
 #include <sstream>
 
 #include <bits/alloc_traits.h>
diff --git a/libstdc++-v3/include/std/system_error b/libstdc++-v3/include/std/system_error
index e12bb2f..6dad75d 100644
--- a/libstdc++-v3/include/std/system_error
+++ b/libstdc++-v3/include/std/system_error
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // OS-dependent
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/thread b/libstdc++-v3/include/std/thread
index 82f191a..a314b9e 100644
--- a/libstdc++-v3/include/std/thread
+++ b/libstdc++-v3/include/std/thread
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // concurrency
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/unordered_map b/libstdc++-v3/include/std/unordered_map
index b50ec2a..323edcd 100644
--- a/libstdc++-v3/include/std/unordered_map
+++ b/libstdc++-v3/include/std/unordered_map
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // container
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/unordered_set b/libstdc++-v3/include/std/unordered_set
index edaa517..998417f 100644
--- a/libstdc++-v3/include/std/unordered_set
+++ b/libstdc++-v3/include/std/unordered_set
@@ -31,6 +31,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // containers
+
 #if __cplusplus < 201103L
 # include <bits/c++0x_warning.h>
 #else
diff --git a/libstdc++-v3/include/std/valarray b/libstdc++-v3/include/std/valarray
index 87fec2b..90bbed7 100644
--- a/libstdc++-v3/include/std/valarray
+++ b/libstdc++-v3/include/std/valarray
@@ -33,6 +33,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // <cmath> dependant
+
 #include <bits/c++config.h>
 #include <cmath>
 #include <algorithm>
diff --git a/libstdc++-v3/include/std/vector b/libstdc++-v3/include/std/vector
index d7f69fd..75377d5 100644
--- a/libstdc++-v3/include/std/vector
+++ b/libstdc++-v3/include/std/vector
@@ -57,6 +57,8 @@
 
 #pragma GCC system_header
 
+#include <bits/requires_hosted.h> // container
+
 #include <bits/stl_algobase.h>
 #include <bits/allocator.h>
 #include <bits/stl_construct.h>
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index 3fd5182..397a4aa 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -46,11 +46,11 @@
 
 #if __cplusplus >= 201103L
 // c++11
+#define __cpp_lib_allocator_traits_is_always_equal 201411L
 #define __cpp_lib_is_null_pointer 201309L
 #define __cpp_lib_result_of_sfinae 201210L
 
 #if _GLIBCXX_HOSTED
-# define __cpp_lib_allocator_traits_is_always_equal 201411L
 #if __cplusplus <= 201703L // N.B. updated value in C++20
 # define __cpp_lib_shared_ptr_arrays 201611L
 #endif
@@ -73,35 +73,38 @@
 #if __cpp_impl_coroutine
 # define __cpp_lib_coroutine 201902L
 #endif
+#define __cpp_lib_exchange_function 201304L
+#define __cpp_lib_integer_sequence 201304L
 #define __cpp_lib_integral_constant_callable 201304L
 #define __cpp_lib_is_final 201402L
+#define __cpp_lib_make_reverse_iterator 201402L
+#ifndef _GLIBCXX_DEBUG // PR libstdc++/70303
+# define __cpp_lib_null_iterators 201304L
+#endif
 #define __cpp_lib_transformation_trait_aliases 201304L
+#define __cpp_lib_transparent_operators 201510L
+#define __cpp_lib_tuple_element_t 201402L
+#define __cpp_lib_tuples_by_type 201304L
 
 #if _GLIBCXX_HOSTED
 # define __cpp_lib_chrono_udls 201304L
 # define __cpp_lib_complex_udls 201309L
-# define __cpp_lib_exchange_function 201304L
 # define __cpp_lib_generic_associative_lookup 201304L
-# define __cpp_lib_integer_sequence 201304L
-# define __cpp_lib_make_reverse_iterator 201402L
 # define __cpp_lib_make_unique 201304L
-# ifndef _GLIBCXX_DEBUG // PR libstdc++/70303
-#  define __cpp_lib_null_iterators 201304L
-# endif
 # define __cpp_lib_quoted_string_io 201304L
 # define __cpp_lib_robust_nonmodifying_seq_ops 201304L
 # ifdef _GLIBCXX_HAS_GTHREADS
 #  define __cpp_lib_shared_timed_mutex 201402L
 # endif
 # define __cpp_lib_string_udls 201304L
-# define __cpp_lib_transparent_operators 201510L
-# define __cpp_lib_tuple_element_t 201402L
-# define __cpp_lib_tuples_by_type 201304L
 #endif
 
 #if __cplusplus >= 201703L
 // c++17
 #define __cpp_lib_addressof_constexpr 201603L
+#define __cpp_lib_any 201606L
+#define __cpp_lib_apply 201603L
+#define __cpp_lib_as_const 201510L
 #define __cpp_lib_atomic_is_always_lock_free 201603L
 #define __cpp_lib_bool_constant 201505L
 #define __cpp_lib_byte 201603L
@@ -111,6 +114,7 @@
 #ifdef __GCC_DESTRUCTIVE_SIZE
 # define __cpp_lib_hardware_interference_size 201703L
 #endif
+#define __cpp_lib_invoke 201411L
 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE
 # define __cpp_lib_is_aggregate 201703L
 #endif
@@ -120,17 +124,23 @@
 # define __cpp_lib_launder 201606L
 #endif
 #define __cpp_lib_logical_traits 201510L
+#define __cpp_lib_make_from_tuple 201606L
+#define __cpp_lib_not_fn 201603L
+#if __cplusplus == 201703L // N.B. updated value in C++20
+# define __cpp_lib_optional 201606L
+#endif
 #define __cpp_lib_type_trait_variable_templates 201510L
 #define __cpp_lib_uncaught_exceptions 201411L
+#if !(__cpp_concepts >= 202002L && __cpp_constexpr >= 201811L)
+// N.B. updated value in C++20
+# define __cpp_lib_variant 202102L
+#endif
 #define __cpp_lib_void_t 201411L
 
 #if _GLIBCXX_HOSTED
-#define __cpp_lib_any 201606L
-#define __cpp_lib_apply 201603L
 #if __cplusplus == 201703L // N.B. updated value in C++20
 # define __cpp_lib_array_constexpr 201803L
 #endif
-#define __cpp_lib_as_const 201510L
 #define __cpp_lib_boyer_moore_searcher 201603L
 #define __cpp_lib_chrono 201611L
 #define __cpp_lib_clamp 201603L
@@ -146,9 +156,7 @@
 #define __cpp_lib_gcd 201606L
 #define __cpp_lib_gcd_lcm 201606L
 #define __cpp_lib_hypot 201603L
-#define __cpp_lib_invoke 201411L
 #define __cpp_lib_lcm 201606L
-#define __cpp_lib_make_from_tuple 201606L
 #define __cpp_lib_map_try_emplace 201411L
 #define __cpp_lib_math_special_functions 201603L
 #ifdef _GLIBCXX_HAS_GTHREADS
@@ -158,10 +166,6 @@
 #endif
 #define __cpp_lib_node_extract 201606L
 #define __cpp_lib_nonmember_container_access 201411L
-#define __cpp_lib_not_fn 201603L
-#if __cplusplus == 201703L // N.B. updated value in C++20
-# define __cpp_lib_optional 201606L
-#endif
 #define __cpp_lib_parallel_algorithm 201603L
 #define __cpp_lib_raw_memory_algorithms 201606L
 #define __cpp_lib_sample 201603L
@@ -176,18 +180,16 @@
 # define __cpp_lib_to_chars 201611L
 #endif
 #define __cpp_lib_unordered_map_try_emplace 201411L
-#if !(__cpp_concepts >= 202002L && __cpp_constexpr >= 201811L)
-// N.B. updated value in C++20
-# define __cpp_lib_variant 202102L
-#endif
 #endif
 
 #if __cplusplus >= 202002L
 // c++20
+#define __cpp_lib_assume_aligned 201811L
 #define __cpp_lib_atomic_flag_test 201907L
 #define __cpp_lib_atomic_float 201711L
 #define __cpp_lib_atomic_ref 201806L
 #define __cpp_lib_atomic_value_initialization 201911L
+#define __cpp_lib_bind_front 201907L
 #if __has_builtin(__builtin_bit_cast)
 # define __cpp_lib_bit_cast 201806L
 #endif
@@ -202,6 +204,7 @@
 #endif
 #define __cpp_lib_endian 201907L
 #define __cpp_lib_int_pow2 202002L
+#define __cpp_lib_integer_comparison_functions 202002L
 #ifdef _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED
 # define __cpp_lib_is_constant_evaluated 201811L
 #endif
@@ -214,19 +217,32 @@
  && __has_builtin(__builtin_is_pointer_interconvertible_with_class)
 # define __cpp_lib_is_pointer_interconvertible 201907L
 #endif
+#define __cpp_lib_math_constants 201907L
+#if __cpp_lib_concepts
+# define __cpp_lib_make_obj_using_allocator 201811L
+#endif
+#define __cpp_lib_optional 202106L
 #define __cpp_lib_remove_cvref 201711L
 #if __has_builtin(__builtin_source_location)
 # define __cpp_lib_source_location 201907L
 #endif
+#if __cpp_lib_concepts
+# define __cpp_lib_span 202002L
+#endif
+#define __cpp_lib_ssize 201902L
 #if __cpp_impl_three_way_comparison >= 201907L && __cpp_lib_concepts
 # define __cpp_lib_three_way_comparison 201907L
 #endif
+#define __cpp_lib_to_address 201711L
+#define __cpp_lib_to_array 201907L
 #define __cpp_lib_type_identity 201806L
 #define __cpp_lib_unwrap_ref 201811L
+#if __cpp_concepts >= 202002L && __cpp_constexpr >= 201811L
+# define __cpp_lib_variant 202106L
+#endif
 
 #if _GLIBCXX_HOSTED
 #define __cpp_lib_array_constexpr 201811L
-#define __cpp_lib_assume_aligned 201811L
 #define __cpp_lib_atomic_shared_ptr 201711L
 #if defined _GLIBCXX_HAS_GTHREADS || defined _GLIBCXX_HAVE_LINUX_FUTEX
 # define __cpp_lib_atomic_wait 201907L
@@ -234,9 +250,7 @@
 #  define __cpp_lib_barrier 201907L
 # endif
 #endif
-#define __cpp_lib_bind_front 201907L
 // FIXME: #define __cpp_lib_execution 201902L
-#define __cpp_lib_integer_comparison_functions 202002L
 #define __cpp_lib_constexpr_algorithms 201806L
 #ifdef __cpp_lib_is_constant_evaluated
 # define __cpp_lib_constexpr_char_traits 201811L
@@ -268,11 +282,6 @@
 # define __cpp_lib_latch 201907L
 #endif
 #define __cpp_lib_list_remove_return_type 201806L
-#if __cpp_lib_concepts
-# define __cpp_lib_make_obj_using_allocator 201811L
-#endif
-#define __cpp_lib_math_constants 201907L
-#define __cpp_lib_optional 202106L
 #define __cpp_lib_polymorphic_allocator 201902L
 #if __cpp_lib_concepts
 # define __cpp_lib_ranges 202110L
@@ -283,28 +292,29 @@
 #define __cpp_lib_shared_ptr_arrays 201707L
 #define __cpp_lib_shift 201806L
 #define __cpp_lib_smart_ptr_for_overwrite 202002L
-#if __cpp_lib_concepts
-# define __cpp_lib_span 202002L
-#endif
-#define __cpp_lib_ssize 201902L
 #define __cpp_lib_starts_ends_with 201711L
 # if _GLIBCXX_USE_CXX11_ABI
 // Only supported with cxx11-abi
 #  define __cpp_lib_syncbuf 201803L
 # endif
-#define __cpp_lib_to_address 201711L
-#define __cpp_lib_to_array 201907L
-#if __cpp_concepts >= 202002L && __cpp_constexpr >= 201811L
-# define __cpp_lib_variant 202106L
-#endif
 #endif
 
 #if __cplusplus > 202002L
 // c++23
 #define __cpp_lib_byteswap 202110L
 #define __cpp_lib_constexpr_typeinfo 202106L
+#if __cpp_concepts >= 202002L
+# define __cpp_lib_expected 202202L
+#endif
+#define __cpp_lib_invoke_r 202106L
 #define __cpp_lib_is_scoped_enum 202011L
+#if __cpp_lib_concepts
+# undef __cpp_lib_optional
+# define __cpp_lib_optional 202110L
+#endif
 #define __cpp_lib_reference_from_temporary 202202L
+#define __cpp_lib_to_underlying 202102L
+#define __cpp_lib_unreachable 202202L
 
 #if _GLIBCXX_HOSTED
 #define __cpp_lib_adaptor_iterator_pair_constructor 202106L
@@ -313,15 +323,7 @@
 # undef __cpp_lib_constexpr_memory
 # define __cpp_lib_constexpr_memory 202202L
 #endif
-#if __cpp_concepts >= 202002L
-# define __cpp_lib_expected 202202L
-#endif
-#define __cpp_lib_invoke_r 202106L
 #define __cpp_lib_ios_noreplace 202207L
-#if __cpp_lib_concepts
-# undef __cpp_lib_optional
-# define __cpp_lib_optional 202110L
-#endif
 #define __cpp_lib_move_only_function 202110L
 #if __cpp_lib_span
 # define __cpp_lib_spanstream 202106L
@@ -334,8 +336,6 @@
 #if _GLIBCXX_USE_CXX11_ABI // Only supported with cxx11-abi
 # define __cpp_lib_string_resize_and_overwrite 202110L
 #endif
-#define __cpp_lib_to_underlying 202102L
-#define __cpp_lib_unreachable 202202L
 #endif
 #endif // C++23
 #endif // C++20