[Bug target/114968] [14/15 Regression] missing `__thiscall` attribute on builtin declaration of `__cxa_thread_atexit()`

[lh_mouse at 126 dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114968

--- Comment #24 from LIU Hao <lh_mouse at 126 dot com> ---
GCC 14 branch built successfully on i686-w64-mingw32 with the backported
commit. I have also built boost 1.84 successfully.

I'm now trying to fix the LD fault..