use AC_CHECK_FUNCS_ONCE, not AC_CHECK_FUNCS in modules/* * modules/pipe-filter-gi: Use AC_CHECK_FUNCS_ONCE, not AC_CHECK_FUNCS. * modules/pipe-filter-ii: Likewise. * modules/sys_socket-tests: Likewise. * modules/tsearch-tests: Likewise. * Makefile (sc_prefer_ac_check_funcs_once): New rule. (check): Depend on it.