diff --git a/gtk/tests/Makefile.am b/gtk/tests/Makefile.am
index 5486155670..4b2d3440ef 100644
--- a/gtk/tests/Makefile.am
+++ b/gtk/tests/Makefile.am
@@ -28,7 +28,16 @@ testing_SOURCES			 = testing.c
 testing_LDADD			 = $(progs_ldadd)
 
 TEST_PROGS			+= treemodel
-treemodel_SOURCES		 = treemodel.c liststore.c treestore.c filtermodel.c sortmodel.c modelrefcount.c gtktreemodelrefcount.c
+treemodel_SOURCES		 = \
+				treemodel.h \
+				treemodel.c \
+				liststore.c \
+				treestore.c \
+				filtermodel.c \
+				sortmodel.c \
+				modelrefcount.c \
+				gtktreemodelrefcount.h \
+				gtktreemodelrefcount.c
 treemodel_LDADD			 = $(progs_ldadd)
 
 TEST_PROGS			+= treeview