Cocoa: add callback for application specific Extended keys and non-US keyboards handling.

lcl/interfaces/cocoa/cocoaconfig.inc

@@ -39,6 +39,8 @@ var
       highestHandler: nil;
       // Event to call when there is no MainForm with MainForm.close
       onQuitApp: nil;
+      // Platform key Event modification function
+      keyEventToVK: nil;
     );
   );
 

lcl/interfaces/cocoa/cocoaconfig.pas

@@ -148,10 +148,13 @@ type
   TCocoaApplicationEventHandler = function( event: NSEvent ): Boolean of object;
   // Need to pass to QueueAsyncCall which takes TDataEvent
   TCocoaApplicationOnAppQuitEvent = TDataEvent;
+  // Platform specific NSEvent key translation to VK Keycode function
+  TCocoaApplicationEventToVK = function(AEvent: NSEvent): Word;
 
   TCocoaConfigApplicationEvents = record
     highestHandler: TCocoaApplicationEventHandler;
     onQuitApp: TCocoaApplicationOnAppQuitEvent;
+    keyEventToVK: TCocoaApplicationEventToVK;
   end;
 
   TCocoaConfigApplication = record

lcl/interfaces/cocoa/cocoawscommon.pas

@@ -595,6 +595,9 @@ begin
   else
     VKKeyCode := MacCodeToVK(KeyCode);
 
+  if Assigned(CocoaConfigApplication.events.keyEventToVK) then
+    VKKeyCode := CocoaConfigApplication.events.keyEventToVK(Event);
+
   case VKKeyCode of
     // for sure, these are "non-printable" keys (see http://wiki.lazarus.freepascal.org/LCL_Key_Handling)
     VK_F1..VK_F24,                     // Function keys (F1-F12)