The possible base classes of std::allocator are new_allocator and
malloc_allocator, which both cause a non-reserved name to be declared in
every program that includes the definition of std::allocator. This is
non-conforming.

This change replaces __gnu_cxx::new_allocator with std::__new_allocator
which is identical except for using a reserved name. The non-standard
extension __gnu_cxx::new_allocator is preserved as a thin wrapper over
std::__new_allocator. There is no problem with the extension using a
non-reserved name now that it's not included by default in other
headers.

The same change could be done to __gnu_cxx::malloc_allocator but as it's
not the default configuration it can wait.

libstdc++-v3/ChangeLog:

	PR libstdc++/64135
	* config/allocator/new_allocator_base.h: Include
	<bits/new_allocator.h> instead of <ext/new_allocator.h>.
	(__allocator_base): Use std::__new_allocator instead of
	__gnu_cxx::new_allocator.
	* doc/xml/manual/allocator.xml: Document new default base class
	for std::allocator.
	* doc/xml/manual/evolution.xml: Likewise.
	* doc/html/*: Regenerate.
	* include/Makefile.am: Add bits/new_allocator.h.
	* include/Makefile.in: Regenerate.
	* include/experimental/memory_resource (new_delete_resource):
	Use std::__new_allocator instead of __gnu_cxx::new_allocator.
	* include/ext/new_allocator.h (new_allocator): Derive from
	std::__new_allocator. Move implementation to ...
	* include/bits/new_allocator.h: New file.
	* testsuite/20_util/allocator/64135.cc: New test.

The bitmap_allocator, __mt_alloc and __pool_alloc extensions are no
longer suitable for use as the base class of std::allocator, because
they have not been updated to meet the C++20 requirements.  There is a
patch attached to PR 103340 which addresses that, but more work would be
needed to solve the linking errors that occur when the library is
configured to use them.

Using --enable-libstdcxx-allocator=bitmap wouldn't even bootstrap for
the past few years, and I can't find any gcc-testresults reports using
any of these allocators. This patch removes the configure option to use
these as the std::allocator base class. The allocators are still in the
tree and can be used directly, you just can't configure the library to
use one of them as the base class of std::allocator.

libstdc++-v3/ChangeLog:

	PR libstdc++/103340
	PR libstdc++/103400
	PR libstdc++/103381
	* acinclude.m4 (GLIBCXX_ENABLE_ALLOCATOR): Remove mt, bitmap
	and pool options.
	* configure: Regenerate.
	* config/allocator/bitmap_allocator_base.h: Removed.
	* config/allocator/mt_allocator_base.h: Removed.
	* config/allocator/pool_allocator_base.h: Removed.
	* doc/xml/manual/allocator.xml: Update.
	* doc/xml/manual/configure.xml: Update.
	* doc/xml/manual/evolution.xml: Document removal.
	* doc/xml/manual/mt_allocator.xml: Editorial tweaks.
	* doc/html/manual/*: Regenerate.

Clang doesn't define __SANITIZE_ADDRESS__ so use its __has_feature check
to detect Asan instead.

libstdc++-v3/ChangeLog:

	PR libstdc++/103453
	* config/allocator/malloc_allocator_base.h
	(_GLIBCXX_SANITIZE_STD_ALLOCATOR): Define for Clang.
	* config/allocator/new_allocator_base.h
	(_GLIBCXX_SANITIZE_STD_ALLOCATOR): Likewise.

From-SVN: r279813

	* config/allocator/new_allocator_base.h (__allocator_base): Add
	workaround for Doxygen bug #6945.
	* include/std/memory: Improve docs. Define group for pointer safety.
	* include/std/scoped_allocator: Improve docs. Use "undocumented"
	conditional to suppress documentation for implementation details.

From-SVN: r270807