[Bug libstdc++/110432] macOS: Segmentation fault when using stdlibc++ from gcc 13.1 in combination with clang-16

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110432

--- Comment #16 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:61bf34d17473d611bb2695329808810dbd5af478

commit r13-7591-g61bf34d17473d611bb2695329808810dbd5af478
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jun 30 11:07:35 2023 +0100

    libstdc++: Fix iostream init for Clang on darwin [PR110432]

    The __has_attribute(init_priority) check in <iostream> is true for Clang
    on darwin, which means that user code including <iostream> thinks the
    library will initialize the global streams. However, when libstdc++ is
    built by GCC on darwin, the __has_attribute(init_priority) check is
    false, which means that the library thinks that user code will do the
    initialization when <iostream> is included. This means that the
    initialization is never done.

    Add an autoconf check so that the header and the library both make their
    decision based on the static properties of GCC at build time, with a
    consistent outcome.

    As a belt and braces check, also do the initialization in <iostream> if
    the compiler including that header doesn't support the attribute (even
    if the library also containers the initialization). This might result in
    redundant initialization done in <iostream>, but ensures the
    initialization happens somewhere if there's any doubt about the
    attribute working correctly due to missing linker support.

    libstdc++-v3/ChangeLog:

            PR libstdc++/110432
            * acinclude.m4 (GLIBCXX_CHECK_INIT_PRIORITY): New.
            * config.h.in: Regenerate.
            * configure: Regenerate.
            * configure.ac: Use GLIBCXX_CHECK_INIT_PRIORITY.
            * include/std/iostream: Use new autoconf macro as well as
            __has_attribute.
            * src/c++98/ios_base_init.h: Use new autoconf macro instead of
            __has_attribute.

    Reviewed-by: Patrick Palka <ppalka@redhat.com>
    (cherry picked from commit fe2651affa8c15624188bfd062fb894648743431)