dirstamp: revert change of Jan 11 2023. Fixes (hopefully) automake bug https://bugs.gnu.org/61867. * bin/automake.in: restore explicit per-directory pattern rules, since evidently @D is not supported on BSD-derived makes, whatever POSIX says. That is, revert this commit: https://git.savannah.gnu.org/gitweb/?p=automake.git;a=commitdiff;h=55f8fcfd08cbf15d65d61dd2db934b6c3171cf06