diff --git a/lib/getopt-pfx-core.h b/lib/getopt-pfx-core.h
index da0a6d0c3c4..ec545c1b51c 100644
--- a/lib/getopt-pfx-core.h
+++ b/lib/getopt-pfx-core.h
@@ -48,6 +48,14 @@
 # define optind __GETOPT_ID (optind)
 # define optopt __GETOPT_ID (optopt)
 
+/* Work around a a problem on macOS, which declares getopt with a
+   trailing __DARWIN_ALIAS(getopt) that would expand to something like
+   __asm("_" "rpl_getopt" "$UNIX2003") were it not for the following
+   hack to suppress the macOS declaration <https://bugs.gnu.org/40205>.  */
+# ifdef __APPLE__
+#  define _GETOPT
+# endif
+
 /* The system's getopt.h may have already included getopt-core.h to
    declare the unprefixed identifiers.  Undef _GETOPT_CORE_H so that
    getopt-core.h declares them with prefixes.  */
diff --git a/m4/acl.m4 b/m4/acl.m4
index e459451ae31..a3dcf9357b9 100644
--- a/m4/acl.m4
+++ b/m4/acl.m4
@@ -1,5 +1,5 @@
 # acl.m4 - check for access control list (ACL) primitives
-# serial 23
+# serial 24
 
 # Copyright (C) 2002, 2004-2020 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -139,7 +139,7 @@ int type = ACL_TYPE_EXTENDED;]])],
       AC_MSG_WARN([AC_PACKAGE_NAME will be built without ACL support.])
     fi
   fi
-  test $gl_need_lib_has_acl && LIB_HAS_ACL=$LIB_ACL
+  test -n "$gl_need_lib_has_acl" && LIB_HAS_ACL=$LIB_ACL
   AC_SUBST([LIB_ACL])
   AC_DEFINE_UNQUOTED([USE_ACL], [$use_acl],
     [Define to nonzero if you want access control list support.])