Deprecate --glx-swap-method

Setting glx-swap-method to value other than "undefined" and "buffer-age"
could potentially cause rendering problems. So remove them, the meaning
of the remaining options can be more precisely captured by "use-damage",
so create a new option under that name.

--glx-swap-method is deprecated in favor of the new option --use-damage.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/opengl.c

@@ -53,11 +53,6 @@ bool glx_init(session_t *ps, bool need_render) {
 		}
 	}
 
-	if (ps->o.glx_swap_method > CGLX_MAX_BUFFER_AGE) {
-		log_error("glx-swap-method is too big");
-		goto glx_init_end;
-	}
-
 	// Get XVisualInfo
 	pvis = get_visualinfo_from_visual(ps, ps->vis);
 	if (!pvis) {