https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120697
--- Comment #8 from Sam James <sjames at gcc dot gnu.org> --- Please try: ~/git/gcc/configure CFLAGS="-O2 -fstack-clash-protection" CXXFLAGS="-O2 -fstack-clash-protection" BOOT_CFLAGS="-O2 -fstack-clash-protection" BOOT_CXXFLAGS="-O2 -fstack-clash-protection" CFLAGS_FOR_TARGET="-O2 -fstack-clash-protection" CXXFLAGS_FOR_TARGET="-O2 -fstack-clash-protection" make