https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58929
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> --- The GNU libc has no-op stubs for several pthread functions. I think that is done so that single threaded programs which don't actually need those functions can still link to libraries that have references to those functions. They don't block because they're not for use in multithreaded programs. If you need the real versions you need to link to libpthread.
