Oskar Linde fixed bug #507

Trackpad scrolling on OSX is broken. Scrolling up/slightly right gets
translated into a Down event in SDL. The following patch fixes this extremely
irritating issue:

--HG--
branch : SDL-1.2
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/branches/SDL-1.2%402650

src/video/quartz/SDL_QuartzEvents.m

@@ -930,10 +930,12 @@ void QZ_PumpEvents (_THIS)
                         Uint8 button;
                         dy = [ event deltaY ];
                         dx = [ event deltaX ];
-                        if ( dy > 0.0 || dx > 0.0 ) /* Scroll up */
+                        if ( dy > 0.0 ) /* Scroll up */
                             button = SDL_BUTTON_WHEELUP;
-                        else /* Scroll down */
+                        else if ( dy < 0.0 ) /* Scroll down */
                             button = SDL_BUTTON_WHEELDOWN;
+                        else
+                            break; /* Horizontal scroll */
                         /* For now, wheel is sent as a quick down+up */
                         SDL_PrivateMouseButton (SDL_PRESSED, button, 0, 0);
                         SDL_PrivateMouseButton (SDL_RELEASED, button, 0, 0);