reftests: Use $(NULL) in the Makefile

diff --git a/tests/reftests/Makefile.am b/tests/reftests/Makefile.am
index 3d8b3b61e34564644625973fd93d8dfb2360a698..e5d9d032d46b5d7f2e983298514cc337c715ac58 100644 (file)
--- a/tests/reftests/Makefile.am
+++ b/tests/reftests/Makefile.am
@@ -1,4 +1,5 @@
 include $(top_srcdir)/Makefile.decl
+NULL =
 
 TEST_PROGS += gtk-reftest
 
@@ -272,6 +273,7 @@ EXTRA_DIST += \
        unresolvable.ref.ui \
        unresolvable.ui \
        window-default-size.ref.ui \
-       window-default-size.ui
+       window-default-size.ui \
+       $(NULL)
 
 -include $(top_srcdir)/git.mk