diff --git a/Makefile.am b/Makefile.am
index fb949f7..93c7029 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -83,3 +83,7 @@ TEST_EXTENSIONS = .scm
 SCM_LOG_COMPILER = $(top_builddir)/pre-inst-env $(GUILE)
 
 CLEANFILES = $(GOBJECTS) $(SCM_TESTS:tests/%.scm=%.log)
+
+EXTRA_DIST =                                    \
+  system/foreign/unions-read-write.scm          \
+  system/foreign/unions.scm