https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82920
--- Comment #3 from Iain Sandoe <iains at gcc dot gnu.org> --- I believe that the target-supports test needs the -fcf-protection flag to ensure that code generated is appropriate (the endbr* insns are not accepted yet by the Xcode assembler, although they will be at some point, since LLVM 7 does).
