[Bug driver/103949] gcc fails to provide a standard conforming C11 or C++17 environment even when specifying -std=c11 or -std=c++17

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103949

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
If you want __STDC_NO_THREADS defined file a bug about that but gcc will need
to record which versions of glibc has C11 thread defined or not.
You could use __has_include extension which will handle that mostly for you
really.