libstdc++: Add preprocessor conditions for freestanding [PR106953]

This adds checks for _GLIBCXX_HOSTED to a number of headers which are
not currently installed for freestanding, but need to be for P1642R11
support. For example, <iterator> needs to be installed for C++23
freestanding mode, but without stream iterators and streambuf iterators.
Similarly, <memory> needs to be installed, but without std::allocator
and std::shared_ptr. This change disables the non-freestanding parts of
those headers.

libstdc++-v3/ChangeLog:

	PR libstdc++/106953
	* include/backward/auto_ptr.h [!_GLIBCXX_HOSTED]: Do not define
	shared_ptr members.
	* include/bits/alloc_traits.h [!_GLIBCXX_HOSTED]: Do not declare
	std::allocator_traits<std::allocator<T>> specializations for
	freestanding.
	* include/bits/memoryfwd.h [!_GLIBCXX_HOSTED] (allocator): Do
	not declare for freestanding.
	* include/bits/stl_algo.h [!_GLIBCXX_HOSTED] (stable_partition):
	Do not define for freestanding.
	[!_GLIBCXX_HOSTED] (merge, stable_sort): Do not use temporary
	buffers for freestanding.
	* include/bits/stl_algobase.h [!_GLIBCXX_HOSTED]: Do not declare
	streambuf iterators and overloaded algorithms using them.
	* include/bits/stl_uninitialized.h [!_GLIBCXX_HOSTED]: Do not
	define specialized overloads for std::allocator.
	* include/bits/unique_ptr.h [!_GLIBCXX_HOSTED] (make_unique)
	(make_unique_for_overwrite, operator<<): Do not define for
	freestanding.
	* include/c_global/cstdlib [!_GLIBCXX_HOSTED] (_Exit): Declare.
	Use _GLIBCXX_NOTHROW instead of throw().
	* include/debug/assertions.h [!_GLIBCXX_HOSTED]: Ignore
	_GLIBCXX_DEBUG for freestanding.
	* include/debug/debug.h [!_GLIBCXX_DEBUG]: Likewise.
	* include/std/bit [!_GLIBCXX_HOSTED]: Do not use the custom
	__int_traits if <ext/numeric_traits.h> is available.
	* include/std/functional [!_GLIBCXX_HOSTED]: Do not include
	headers that aren't valid for freestanding.
	(boyer_moore_searcher, boyer_moore_horspool_searcher): Do not
	define for freestanding.
	* include/std/iterator [!_GLIBCXX_HOSTED]: Do not include
	headers that aren't valid for freestanding.
	* include/std/memory [!_GLIBCXX_HOSTED]: Likewise.
	* include/std/ranges [!_GLIBCXX_HOSTED] (istream_view): Do not
	define for freestanding.
	(views::__detail::__is_basic_string_view) [!_GLIBCXX_HOSTED]:
	Do not define partial specialization for freestanding.

1 files changed, 14 insertions, 10 deletions

diff --git a/libstdc++-v3/include/c_global/cstdlib b/libstdc++-v3/include/c_global/cstdlib
index 8a832af..0f7362e 100644
--- a/libstdc++-v3/include/c_global/cstdlib
+++ b/libstdc++-v3/include/c_global/cstdlib
@@ -51,19 +51,23 @@
 
 #define EXIT_SUCCESS 0
 #define EXIT_FAILURE 1
+#define NULL __null
 
 namespace std
 {
-  extern "C" void abort(void) throw () _GLIBCXX_NORETURN;
-  extern "C" int atexit(void (*)(void)) throw ();
-  extern "C" void exit(int) throw () _GLIBCXX_NORETURN;
+  extern "C" void abort(void) _GLIBCXX_NOTHROW _GLIBCXX_NORETURN;
+  extern "C" int atexit(void (*)(void)) _GLIBCXX_NOTHROW;
+  extern "C" void exit(int) _GLIBCXX_NOTHROW _GLIBCXX_NORETURN;
 #if __cplusplus >= 201103L
 # ifdef _GLIBCXX_HAVE_AT_QUICK_EXIT
-  extern "C" int at_quick_exit(void (*)(void)) throw ();
+  extern "C" int at_quick_exit(void (*)(void)) _GLIBCXX_NOTHROW;
 # endif
 # ifdef _GLIBCXX_HAVE_QUICK_EXIT
-  extern "C" void quick_exit(int) throw() _GLIBCXX_NORETURN;
+  extern "C" void quick_exit(int) _GLIBCXX_NOTHROW_GLIBCXX_NORETURN;
 # endif
+#if _GLIBCXX_USE_C99_STDLIB
+  extern "C" void _Exit(int) _GLIBCXX_NOTHROW _GLIBCXX_NORETURN;
+#endif
 #endif
 } // namespace std
 
@@ -174,7 +178,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #ifndef __CORRECT_ISO_CPP_STDLIB_H_PROTO
   inline ldiv_t
-  div(long __i, long __j) { return ldiv(__i, __j); }
+  div(long __i, long __j) _GLIBCXX_NOTHROW { return ldiv(__i, __j); }
 #endif
 
 
@@ -200,7 +204,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   using ::lldiv_t;
 #endif
 #if _GLIBCXX_USE_C99_CHECK || _GLIBCXX_USE_C99_DYNAMIC
-  extern "C" void (_Exit)(int) throw () _GLIBCXX_NORETURN;
+  extern "C" void (_Exit)(int) _GLIBCXX_NOTHROW _GLIBCXX_NORETURN;
 #endif
 #if !_GLIBCXX_USE_C99_DYNAMIC
   using ::_Exit;
@@ -217,11 +221,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
 
 #if _GLIBCXX_USE_C99_LONG_LONG_CHECK || _GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
-  extern "C" long long int (atoll)(const char *) throw ();
+  extern "C" long long int (atoll)(const char *) _GLIBCXX_NOTHROW;
   extern "C" long long int
-    (strtoll)(const char * __restrict, char ** __restrict, int) throw ();
+    (strtoll)(const char * __restrict, char ** __restrict, int) _GLIBCXX_NOTHROW;
   extern "C" unsigned long long int
-    (strtoull)(const char * __restrict, char ** __restrict, int) throw ();
+    (strtoull)(const char * __restrict, char ** __restrict, int) _GLIBCXX_NOTHROW;
 #endif
 #if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
   using ::atoll;