setup-hooks: compress-man-pages.sh: Do not attempt to compress .xz files

pkgs/build-support/setup-hooks/compress-man-pages.sh

···
     echo "gzipping man pages under $dir/share/man/"
 
     # Compress all uncompressed manpages.  Don't follow symlinks, etc.
-    find "$dir"/share/man/ -type f -a '!' -regex '.*\.\(bz2\|gz\)$' -print0 \
+    find "$dir"/share/man/ -type f -a '!' -regex '.*\.\(bz2\|gz\|xz\)$' -print0 \
         | while IFS= read -r -d $'\0' f
     do
         if gzip -c -n "$f" > "$f".gz; then
···
     done
 
     # Point symlinks to compressed manpages.
-    find "$dir"/share/man/ -type l -a '!' -regex '.*\.\(bz2\|gz\)$' -print0 \
+    find "$dir"/share/man/ -type l -a '!' -regex '.*\.\(bz2\|gz\|xz\)$' -print0 \
         | sort -z \
         | while IFS= read -r -d $'\0' f
     do