diff --git a/src/include/catalog/duplicate_oids b/src/include/catalog/duplicate_oids
index 5d87234d22..ebcea8f2ec 100755
--- a/src/include/catalog/duplicate_oids
+++ b/src/include/catalog/duplicate_oids
@@ -5,6 +5,8 @@
 # finds oids that are duplicated in the system tables.
 #
 
+FILES=`ls pg_*.h`
+
 #
 # The previous version did not use the -d option on uniq
 # so check here that it is supported.