Cocoa: Add comments for Cocoa symbol macros

(cherry picked from commit 94cb0347ab)

src/cocoa_platform.h

@@ -41,6 +41,9 @@
 typedef void* id;
 #endif
 
+// NOTE: Many Cocoa enum values have been renamed and we need to build across
+//       SDK versions where one is unavailable or the other deprecated
+//       We use the newer names in code and these macros to handle compatibility
 #if MAC_OS_X_VERSION_MAX_ALLOWED < 101200
  #define NSBitmapFormatAlphaNonpremultiplied NSAlphaNonpremultipliedBitmapFormat
  #define NSEventMaskAny NSAnyEventMask

src/nsgl_context.h

@@ -24,6 +24,9 @@
 //
 //========================================================================
 
+// NOTE: Many Cocoa enum values have been renamed and we need to build across
+//       SDK versions where one is unavailable or the other deprecated
+//       We use the newer names in code and these macros to handle compatibility
 #if MAC_OS_X_VERSION_MAX_ALLOWED < 101400
  #define NSOpenGLContextParameterSwapInterval NSOpenGLCPSwapInterval
  #define NSOpenGLContextParameterSurfaceOpacity NSOpenGLCPSurfaceOpacity