diff --git a/.buildbot/undist/01-unpack.sh b/.buildbot/undist/01-unpack.sh
index a657e91..7dd4099 100644
--- a/.buildbot/undist/01-unpack.sh
+++ b/.buildbot/undist/01-unpack.sh
@@ -9,12 +9,12 @@ fi
 
 if test -n "$INSTALL_DIR" ; then
 	mkdir -p "$INSTALL_DIR"
-	tar_opts="--strip-components=1 -C \"$INSTALL_DIR\""
+	set -- --strip-components=1 -C "$INSTALL_DIR"
 fi
 
 case "$DIST_FORMAT" in
 gztar)
-	tar -xzf "$DIST_FILE" $tar_opts
+	tar -xzf "$DIST_FILE" $*
 	;;
 *)
 	echo "Unsupported DIST_FORMAT ($DIST_FORMAT)" >&2