[Bug libstdc++/78968] conflict between gnu's __cxa_thread_atexit and LLVM's/FreeBSD's implementation

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78968

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
It seems entirely wrong for libc to be providing any __cxa entry point called
by the compiler, such as __cxa_thread_atexit. It should come from the C++
runtime, such as libsupc++, or libcxxabi, or FreeBSD's libcxxrt. We can work
around it, but it's still wrong.