Fix comparison of video modes of equal area

This fixes the bug of video modes being discarded if they had
a different resolution but the same area as another mode.

Upstream: 2777f6a754

glfw/monitor.c

@@ -56,6 +56,10 @@ static int compareVideoModes(const void* fp, const void* sp)
     if (farea != sarea)
         return farea - sarea;
 
+    // Then sort on width
+    if (fm->width != sm->width)
+        return fm->width - sm->width;
+
     // Lastly sort on refresh rate
     return fm->refreshRate - sm->refreshRate;
 }