diff --git a/lib/rb/Makefile.am b/lib/rb/Makefile.am
index 1841065..ab5d903 100644
--- a/lib/rb/Makefile.am
+++ b/lib/rb/Makefile.am
@@ -42,6 +42,9 @@
 dist-hook:
 	$(RM) -r $(distdir)/spec/gen-rb/
 
+distdir:
+	$(MAKE) $(AM_MAKEFLAGS) distdir-am
+
 EXTRA_DIST = \
 	coding_standards.md \
 	Rakefile \