add gitattributes

.gitattributes

@@ -0,0 +1,9 @@
+#  Copyright (C) 2020 Alexandros Theodotou <alex at zrythm dot org>
+#
+# Copying and distribution of this file, with or without modification,
+# are permitted in any medium without royalty provided the copyright
+# notice and this notice are preserved.  This file is offered as-is,
+# without any warranty.
+
+# add vendored paths
+ext/** linguist-vendored