intel: Replace the non-getBuffersWithFormat compat path with an error message.

It's been broken (using NULL getBuffersWithFormat() instead of
getBuffers()) due to a copy and paste error for a year now.
GetBuffersWithFormat has been around since 2009, so I don't feel any
guilt in not supporting it.

Reviewed-by: Chad Versace <chad.versace@linux.intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/intel/intel_context.c

@@ -872,27 +872,6 @@ intel_query_dri2_buffers(struct intel_context *intel,
 							   drawable->loaderPrivate);
       free(attachments);
 
-   } else if (screen->dri2.loader) {
-
-      int i = 0;
-      const int max_attachments = 4;
-      unsigned *attachments = calloc(max_attachments, sizeof(unsigned));
-
-      if (intel_get_renderbuffer(fb, BUFFER_FRONT_LEFT))
-	 attachments[i++] = __DRI_BUFFER_FRONT_LEFT;
-      if (intel_get_renderbuffer(fb, BUFFER_BACK_LEFT))
-	 attachments[i++] = __DRI_BUFFER_BACK_LEFT;
-
-      assert(i <= max_attachments);
-
-      *buffers = screen->dri2.loader->getBuffersWithFormat(drawable,
-							   &drawable->w,
-							   &drawable->h,
-							   attachments, i,
-							   buffer_count,
-							   drawable->loaderPrivate);
-      free(attachments);
-
    } else {
       *buffers = NULL;
       *buffer_count = 0;

src/mesa/drivers/dri/intel/intel_screen.c

@@ -810,6 +810,14 @@ __DRIconfig **intelInitScreen2(__DRIscreen *psp)
    int color;
    __DRIconfig **configs = NULL;
 
+   if (psp->dri2.loader->base.version <= 2 ||
+       psp->dri2.loader->getBuffersWithFormat == NULL) {
+      fprintf(stderr,
+	      "\nERROR!  DRI2 loader with getBuffersWithFormat() "
+	      "support required\n");
+      return false;
+   }
+
    /* Allocate the private area */
    intelScreen = CALLOC(sizeof *intelScreen);
    if (!intelScreen) {