diff --git a/panda/src/vision/Sources.pp b/panda/src/vision/Sources.pp
index c28676bf4c..50e06ffdac 100644
--- a/panda/src/vision/Sources.pp
+++ b/panda/src/vision/Sources.pp
@@ -1,4 +1,3 @@
-#define BUILDING_DLL BUILDING_VISION
 #define OTHER_LIBS interrogatedb:c dconfig:c dtoolconfig:m \
                    dtoolutil:c dtoolbase:c dtool:m prc:c movies:m