Mac: Fix incorrect relative jump on focus / start.

We should no longer send huge jumps on relative mode focus changes if
the cursor was moved around, or on initial start.

Fixes http://bugzilla.libsdl.org/show_bug.cgi?id=1836

src/video/cocoa/SDL_cocoamouse.m

@@ -224,10 +224,12 @@ Cocoa_WarpMouse(SDL_Window * window, int x, int y)
     CGWarpMouseCursorPosition(point);
     CGSetLocalEventsSuppressionInterval(0.25);
 
-    /* CGWarpMouseCursorPosition doesn't generate a window event, unlike our
-     * other implementations' APIs.
-     */
-    SDL_SendMouseMotion(mouse->focus, mouse->mouseID, 0, x, y);
+    if (!mouse->relative_mode) {
+        /* CGWarpMouseCursorPosition doesn't generate a window event, unlike our
+         * other implementations' APIs.
+         */
+        SDL_SendMouseMotion(mouse->focus, mouse->mouseID, 0, x, y);
+    }
 }
 
 static int

src/video/cocoa/SDL_cocoawindow.m

@@ -240,12 +240,13 @@ static __inline__ void ConvertNSRect(NSRect *r)
 - (void)windowDidBecomeKey:(NSNotification *)aNotification
 {
     SDL_Window *window = _data->window;
+    SDL_Mouse *mouse = SDL_GetMouse();
 
     /* We're going to get keyboard events, since we're key. */
     SDL_SetKeyboardFocus(window);
 
     /* If we just gained focus we need the updated mouse position */
-    {
+    if (!mouse->relative_mode) {
         NSPoint point;
         int x, y;