Fix build on macOS 11 and earlier whose readlink doesn't have a -f flag.
https://github.com/wxWidgets/wxWidgets/issues/25675
--- configure.orig	2025-05-25 12:15:56.000000000 -0500
+++ configure	2025-08-04 11:12:23.000000000 -0500
@@ -34271,15 +34271,14 @@
             DYLIB_RPATH_POSTLINK="${HOST_PREFIX}install_name_tool -id \$@ \$@"
             cat <<EOF >change-install-names
 #!/bin/sh
-libnames=\$(cd lib ; ls -1 libwx*${WX_RELEASE}.dylib)
+set -ex
+libnames=\$(cd lib ; ls -1 | grep '\.[0-9][0-9]*\.dylib\$')
 changes=''
 for dep in \${libnames} ; do
-    target=\$(readlink -f \${4}/\${dep})
-    changes="\${changes} -change \${target} \${3}/\${dep}"
+    changes="\${changes} -change \${4}/\${dep} \${3}/\${dep}"
 done
 for i in \${libnames} ; do
-    lib=\$(readlink -f \${1}/\${i})
-    ${HOST_PREFIX}install_name_tool \${changes} -id \${3}/\${i} \${lib}
+    ${HOST_PREFIX}install_name_tool \${changes} -id \${3}/\${i} \${1}/\${i}
 done
 
 if test -f "\${2}/wxrc-${WX_RELEASE}" ; then