https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66146
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> --- NetBSD 5 and DragonFly BSD fail the test too. I'm going to make libstdc++ assume pthread_once is not exception-aware unless specifically told otherwise for targets where we know it works, such as x86-linux and (hopefully) glibc > 2.21
