https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58909
--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Maybe libc++ doesn't bother with supporting not linking against -lpthread.
jakub at gcc dot gnu.org via Gcc-bugs Thu, 28 Jan 2021 08:58:37 -0800
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58909
--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Maybe libc++ doesn't bother with supporting not linking against -lpthread.