Recognize macOS 11 and later, remove inaccurate comment, and simplify.
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=44605
--- configure.orig	2020-02-28 13:19:43.000000000 -0600
+++ configure	2022-06-18 17:07:49.000000000 -0500
@@ -8213,16 +8213,11 @@
       _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]*)
+    darwin*)
+      case $MACOSX_DEPLOYMENT_TARGET,$host in
+	10.[012],*|,*powerpc*-darwin[5-8]*)
 	  _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress' ;;
-	10.*)
+	*)
 	  _lt_dar_allow_undefined='${wl}-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;
--- plugins/null/m4/libtool.m4.orig	2020-02-28 13:19:43.000000000 -0600
+++ plugins/null/m4/libtool.m4	2022-06-18 17:42:44.000000000 -0500
@@ -1045,16 +1045,11 @@
       _lt_dar_allow_undefined='${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]]*)
+    darwin*)
+      case $MACOSX_DEPLOYMENT_TARGET,$host in
+	10.[[012]],*|,*powerpc*-darwin[[5-8]]*)
 	  _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress' ;;
-	10.*)
+	*)
 	  _lt_dar_allow_undefined='${wl}-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;
--- plugins/null/configure.orig	2020-02-28 13:19:43.000000000 -0600
+++ plugins/null/configure	2022-06-18 17:19:12.000000000 -0500
@@ -7296,16 +7296,11 @@
       _lt_dar_allow_undefined='${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]*)
+    darwin*)
+      case $MACOSX_DEPLOYMENT_TARGET,$host in
+	10.[012],*|,*powerpc*-darwin[5-8]*)
 	  _lt_dar_allow_undefined='${wl}-flat_namespace ${wl}-undefined ${wl}suppress' ;;
-	10.*)
+	*)
 	  _lt_dar_allow_undefined='${wl}-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;
--- plugins/python/configure.orig	2020-02-28 13:19:43.000000000 -0600
+++ plugins/python/configure	2022-06-18 17:20:31.000000000 -0500
@@ -7571,16 +7571,11 @@
       _lt_dar_allow_undefined='$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][,.]*)
+    darwin*)
+      case $MACOSX_DEPLOYMENT_TARGET,$host in
+	10.[012],*|,*powerpc*-darwin[5-8]*)
 	  _lt_dar_allow_undefined='$wl-flat_namespace $wl-undefined ${wl}suppress' ;;
-	10.*)
+	*)
 	  _lt_dar_allow_undefined='$wl-undefined ${wl}dynamic_lookup' ;;
       esac
     ;;