https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80881
--- Comment #90 from LIU Hao <lh_mouse at 126 dot com> --- As mentioned yesterday, the libstdc++ `call_once` has to be reimplemented to get rid of `__once_callable` and `__once_call` which can't be exported from libstdc++ DLL. You might want to introduce a builtin macro for native TLS, so in the case of that, 'src/c++11/mutex.cc' will be mostly empty.
