https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103021
--- Comment #1 from Eric Gallager <egallager at gcc dot gnu.org> --- Note that automake did similarly in the following commit: https://git.savannah.gnu.org/cgit/automake.git/commit/m4?id=d2ccbd7eb38d6a4277d6f42b994eb5a29b1edf29 ...and that commit is part of automake 1.16.4, so updating to automake 1.16.4 would fix this for the directories that use automake. It wouldn't fix it for the directories that don't use automake, though.
