app: limit the tile-cache size to G_MAXINT also in the UI

and #warning about it in the code until GEGL has a guint64 cache size
property.

app/config/gimpgeglconfig.c

@@ -147,9 +147,18 @@ gimp_gegl_config_class_init (GimpGeglConfigClass *klass)
   else
     memory_size = 1 << 30; /* 1GB */
 
+#ifdef __GNUC__
+#warning limiting tile cache size to G_MAXINT
+#endif
+  memory_size = MIN (memory_size, G_MAXINT);
+
   GIMP_CONFIG_INSTALL_PROP_MEMSIZE (object_class, PROP_TILE_CACHE_SIZE,
                                     "tile-cache-size", TILE_CACHE_SIZE_BLURB,
+#if 0
                                     0, MIN (G_MAXSIZE, GIMP_MAX_MEMSIZE),
+#else
+                                    0, MIN (G_MAXINT, GIMP_MAX_MEMSIZE),
+#endif
                                     memory_size,
                                     GIMP_PARAM_STATIC_STRINGS |
                                     GIMP_CONFIG_PARAM_CONFIRM);

app/gegl/gimp-gegl.c

@@ -48,6 +48,10 @@ gimp_gegl_init (Gimp *gimp)
 
   config = GIMP_GEGL_CONFIG (gimp->config);
 
+#ifdef __GNUC__
+#warning limiting tile cache size to G_MAXINT
+#endif
+
   g_object_set (gegl_config (),
                 "tile-width",  TILE_WIDTH,
                 "tile-height", TILE_HEIGHT,