[Bug c++/63287] __STDCPP_THREADS__ is not defined

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63287

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:1d9a8675d379f02f5e39639f469ae8dfcf33fea9

commit r11-5017-g1d9a8675d379f02f5e39639f469ae8dfcf33fea9
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Nov 13 23:23:33 2020 +0100

    c++: Predefine __STDCPP_THREADS__ in the compiler if thread model is not
single [PR63287]

    The following patch predefines __STDCPP_THREADS__ macro to 1 if c++11 or
    later and thread model (e.g. printed by gcc -v) is not single.
    There are two targets not handled by this patch, those that define
    THREAD_MODEL_SPEC.  In one case - QNX - it looks just like a mistake
    to me, instead of setting thread_model=posix in config.gcc it uses
    THREAD_MODEL_SPEC macro to set it unconditionally to posix.
    The other is hpux10, which uses -threads option to decide if threads
    are enabled or not, but that option isn't really passed to the compiler.
    I think that is something that really should be solved in config/pa/
    instead, e.g. in the config/xxx/xxx-c.c targets usually set their own
    predefined macros and it could handle this, and either pass the option
    also to the compiler, or say predefine __STDCPP_THREADS__ if _DCE_THREADS
    macro is defined already (or -D_DCE_THREADS found on the command line),
    or whatever else.

    2020-11-13  Jakub Jelinek  <jakub@redhat.com>

            PR c++/63287
            * c-cppbuiltin.c: Include configargs.h.
            (c_cpp_builtins): For C++11 and later if THREAD_MODEL_SPEC is not
            defined, predefine __STDCPP_THREADS__ to 1 unless thread_model is
            "single".