[committed] libstdc++: Test errno macros directly, not via autoconf [PR 93151]

[Jonathan Wakely]

On 16/12/20 13:38 +0000, Jonathan Wakely wrote:
>This fixes a bug caused by a mismatch between the macros defined by
><errno.h> when GCC is built and the macros defined by <errno.h> when
>users include <system_error>. If the user code is compiled with
>_XOPEN_SOURCE defined to 500 or 600, Darwin suppresses the
>ENOTRECOVERABLE and EOWNERDEAD macros, which are not defined by SUSv3
>(aka POSIX.1-2001).
>
>Since POSIX requires the errno macros to be macros (and not variables or
>enumerators) we can just test for them directly using the preprocessor.
>That means that <system_error> will match what is actuallydefined when
>it's included, not what was defined when GCC was built. With that change
>there is no need for the GLIBCXX_CHECK_SYSTEM_ERROR configure checks and
>they can be removed.
>
>libstdc++-v3/ChangeLog:
>
>	PR libstdc++/93151
>	* acinclude.m4 (GLIBCXX_CHECK_SYSTEM_ERROR): Remove.
>	* configure.ac: Regenerate.

Oops, that changelog was wrong.

>	* config/os/generic/error_constants.h: Test POSIX errno macros
>	directly, instead of corresponding _GLIBCXX_HAVE_EXXX macros.
>	* testsuite/19_diagnostics/headers/system_error/errc_std_c++0x.cc:
>	Likewise.
>	* testsuite/19_diagnostics/headers/system_error/93151.cc: New
>	test.

I forgot to regenerate the autoconf files. Fixed in r11-6229.

Tested powerpc64le-linux. Committed to trunk.

     libstdc++-v3/ChangeLog:

             * config.h.in: Regenerate.
             * configure: Regenerate.