Added glfwPostEmptyEvent.

src/cocoa_window.m

@@ -1147,6 +1147,20 @@ void _glfwPlatformWaitEvents(void)
     _glfwPlatformPollEvents();
 }
 
+void _glfwPlatformPostEmptyEvent(void)
+{
+    NSEvent* event = [NSEvent otherEventWithType:NSApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:nil
+                                         subtype:0
+                                           data1:0
+                                           data2:0];
+    [NSApp postEvent:event atStart:YES];
+}
+
 void _glfwPlatformSetCursorPos(_GLFWwindow* window, double x, double y)
 {
     setModeCursor(window);