diff --git a/Makefile b/Makefile
index 6a8e2a3..25b6a63 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ GTK_CLIENTS=build/gtk2/immodules/im-bogo.so build/gtk3/immodules/im-bogo.so
 build: $(GTK_CLIENTS) build/server
 
 $(GTK_CLIENTS): build/gtk%/immodules/im-bogo.so : main.vala module.vala
-	valac -o $@ $^ --library=im-bogo --pkg=gtk+-$*.0 -X -fPIC -X -shared
+	valac -o $@ $^ --vapi=build/im-bogo.vapi --library=im-bogo --pkg=gtk+-$*.0 -X -fPIC -X -shared
 	sed -e "s;%PWD%;$(PWD);g" -e "s;%GTK_VERSION%;$*;g" immodules.cache.in > build/gtk$*/immodules.cache
 
 build/server: server.vala