. colors allocated henceforth from the resulting image overwrite

the palette colors (sync with 2.0.34) (Rob Leslie)

ext/gd/libgd/gd_topal.c

@@ -772,6 +772,7 @@ LOCAL (void)
       nim->green[icolor] = 255;
       nim->blue[icolor] = 255;
     }
+		nim->open[icolor] = 0;
 #endif
 }