common/hooks: add some hooks moved from xbps-src (not yet used).

common/hooks/post-install/99-remove-empty-dirs.sh

@@ -0,0 +1,10 @@
+# This hooks removes empty dirs and warns about them.
+
+hook() {
+	for f in $(find ${PKGDESTDIR} -type d -empty|sort -r); do
+		_dir="${f##${PKGDESTDIR}}"
+		[ -z "${_dir}" ] && continue
+		rmdir --ignore-fail-on-non-empty -p "$f" &>/dev/null
+		msg_warn "$pkgver: removed empty dir: ${_dir}\n"
+	done
+}