https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77473
--- Comment #3 from Rimvydas (RJ) <rimvydas.jas at gmail dot com> --- Created attachment 39730 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39730&action=edit possible variant to use libc internal status variable On DragonFly libpthread always brings libc so __isthreaded is available. __isthreaded is a special variable that is set by libpthread lib.