diff --git a/src/archutils/Darwin/StepMania.pch b/src/archutils/Darwin/StepMania.pch
index b9e8479d90..5a11b6b8ea 100644
--- a/src/archutils/Darwin/StepMania.pch
+++ b/src/archutils/Darwin/StepMania.pch
@@ -6,6 +6,7 @@
 #endif
 
 #ifdef __OBJC__
+// Cocoa includes OpenGL from Mac OS X 10.5 onward.
 # import <GL/glew.h>
 # import <Cocoa/Cocoa.h>
 #endif