Fix the usual macOS 11 libtool bug.
--- configure.orig	2021-11-08 21:33:52.000000000 +1300
+++ configure	2021-11-08 21:36:31.000000000 +1300
@@ -8818,17 +8818,12 @@
       _lt_dar_allow_undefined='${wl}-undefined ${wl}suppress' ;;
     darwin1.*)
       _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress' ;;
-    darwin*) # darwin 5.x on
-      # if running on 10.5 or later, the deployment target defaults
-      # to the OS version, if on x86, and 10.4, the deployment
-      # target defaults to 10.4. Don't you love it?
-      case ${MACOSX_DEPLOYMENT_TARGET-10.0},$host in
-	10.0,*86*-darwin8*|10.0,*-darwin[91]*)
-	  _lt_dar_allow_undefined='${wl}-undefined ${wl}dynamic_lookup' ;;
-	10.[012]*)
-	  _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress' ;;
-	10.*)
-	  _lt_dar_allow_undefined='${wl}-undefined ${wl}dynamic_lookup' ;;
+    darwin*)
+      case $MACOSX_DEPLOYMENT_TARGET,$host in
+	   10.[012],*|,*powerpc*-darwin[5-8]*)      
+	     _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress' ;;
+	   *)
+	     _lt_dar_allow_undefined='${wl}-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;
   esac