Recognize macOS 12 and later.
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=44605
https://savannah.gnu.org/bugs/?67540
--- configure.orig	2024-06-28 09:01:10.000000000 -0500
+++ configure	2025-09-21 18:07:52.000000000 -0500
@@ -9622,7 +9622,7 @@
 	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
 	10.[012][,.]*)
 	  _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
-	10.*|11.*)
+	*)
 	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;