[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 #15 from LIU Hao <lh_mouse at 126 dot com> ---
Created attachment 58124
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58124&action=edit
proposed patch v2

Update the patch. Did a quick test on i686-w64-mingw32 and seemed to solve the
issue.

Rebuilding everything now.