Fixed a typo that prevented OSX 10.6 builds.

modules/juce_gui_basics/native/juce_mac_Windowing.mm

@@ -320,7 +320,7 @@ void Desktop::Displays::findDisplays()
         d.totalArea = convertDisplayRect ([s frame], mainScreenBottom);
         d.isMain = (i == 0);
 
-       #if defined (MAC_OS_X_VERSION_10_6) && (MAC_OS_X_VERSION_MAX_ALLOWED > MAC_OS_X_VERSION_10_6)
+       #if defined (MAC_OS_X_VERSION_10_7) && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7)
         if ([s respondsToSelector: @selector (backingScaleFactor)])
             d.scale = s.backingScaleFactor;
         else