diff --git a/panda/src/wgldisplay/Sources.pp b/panda/src/wgldisplay/Sources.pp
index 3100d94e01..8e06e59660 100644
--- a/panda/src/wgldisplay/Sources.pp
+++ b/panda/src/wgldisplay/Sources.pp
@@ -1,3 +1,4 @@
+#define DIRECTORY_IF_GL yes
 #define DIRECTORY_IF_WGL yes
 
 #define USE_GL yes