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.
