prepare.sh: print patched dir

prepare.sh

@@ -4,6 +4,7 @@ patch_target() {
   if [ "$(find "$PWD"/gluon_patches/*.patch 2> /dev/null | wc -l)" -ge 1 ]; then
     for patch in "$PWD"/gluon_patches/*.patch; do
       patch --no-backup-if-mismatch -p0 -d "../" -i "$patch"
+      echo "patching $patch on $(../;pwd)"
     done
   fi
 }