compile_fw: Add ccache_clean command and --help

compile_fw

@@ -279,6 +279,17 @@ patch_feeds() {
 	popd
 }
 
+clean_ccache_help="Set persistent ccache paths"
+clean_ccache() {
+	if [ "$(which ccache)" ]; then
+		_report "Cleaning ccache"
+		[ -z "$CCACHE_HOST_DIR" ]   || CCACHE_DIR="$CCACHE_HOST_DIR"   ccache -C
+		[ -z "$CCACHE_TARGET_DIR" ] || CCACHE_DIR="$CCACHE_TARGET_DIR" ccache -C
+	else
+		_report "Not cleaning ccache as you don't have ccache installed"
+	fi
+}
+
 set_ccache_help="Set persistent ccache paths"
 set_ccache() {
 	[ -z "$CCACHE_SET" ] || return 0
@@ -526,7 +537,7 @@ while expr x$1 : x- > /dev/null; do
 			_set_target "$1"
 			shift
 			;;
-		x-h)
+		x-h|x--help)
 			help
 			exit 0
 			;;