+context_end_frame_pre_swap (void)
+{
+ return metrics_end_frame_pre_swap (current_context->metrics);
+}
+
+void
+context_end_frame_post_swap (void)
+{
+ return metrics_end_frame_post_swap (current_context->metrics);
+}
+
+/* Is the given extension available? */
+static bool
+check_extension (const char *extension)