Clarified comment on APIENTRY hack.

src/win32_platform.h

@@ -42,9 +42,9 @@
  #define WIN32_LEAN_AND_MEAN
 #endif
 
-// This is a workaround for the fact that glfw3.h needs to export APIENTRY (to
-// correctly declare a GL_ARB_debug_output callback, for example) but windows.h
-// thinks it is the only one that gets to do so
+// This is a workaround for the fact that glfw3.h needs to export APIENTRY (for
+// example to allow applications to correctly declare a GL_ARB_debug_output
+// callback) but windows.h assumes no one will define APIENTRY before it does
 #undef APIENTRY
 
 // GLFW on Windows is Unicode only and does not work in MBCS mode