diff --git a/build/win32/vs9/Makefile.am b/build/win32/vs9/Makefile.am
index 2a42a88edf..c92017fab2 100644
--- a/build/win32/vs9/Makefile.am
+++ b/build/win32/vs9/Makefile.am
@@ -1,6 +1,6 @@
 include $(top_srcdir)/Makefile.decl
 
-EXTRA_DIST = \
+EXTRA_DIST += \
 	README.txt \
 	gtk+.sln \
 	gtk+.vsprops \