[Bug libstdc++/121811] stdckdint.h fails to compile in C++26 mode in GCC 14

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121811

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
On the other hand, if I'm going to go to all the trouble of adding a new header
then I might as well just backport r15-8036-gd4c7de7dc925e7 and add the working
header to gcc-14.