extensions: panel_config->resource => wl_surface_res.

Change the name to something less ambigious.

include/extensions.h

@@ -9,13 +9,15 @@
 struct background_config {
         wlc_handle output;
         wlc_resource surface;
-        struct wl_resource *resource;
+        // we need the wl_resource of the surface in the destructor
+        struct wl_resource *wl_surface_res;
 };
 
 struct panel_config {
         wlc_handle output;
         wlc_resource surface;
-        struct wl_resource *resource;
+        // we need the wl_resource of the surface in the destructor
+        struct wl_resource *wl_surface_res;
 };
 
 struct desktop_shell_state {

sway/extensions.c

@@ -14,7 +14,7 @@ void background_surface_destructor(struct wl_resource *resource) {
 	int i;
 	for (i = 0; i < desktop_shell.backgrounds->length; ++i) {
 		struct background_config *config = desktop_shell.backgrounds->items[i];
-		if (config->resource == resource) {
+		if (config->wl_surface_res == resource) {
 			list_del(desktop_shell.backgrounds, i);
 			break;
 		}
@@ -26,7 +26,7 @@ void panel_surface_destructor(struct wl_resource *resource) {
 	int i;
 	for (i = 0; i < desktop_shell.panels->length; ++i) {
 		struct panel_config *config = desktop_shell.panels->items[i];
-		if (config->resource == resource) {
+		if (config->wl_surface_res == resource) {
 			list_del(desktop_shell.panels, i);
 			arrange_windows(&root_container, -1, -1);
 			break;
@@ -58,7 +58,7 @@ static void set_background(struct wl_client *client, struct wl_resource *resourc
 	struct background_config *config = malloc(sizeof(struct background_config));
 	config->output = output;
 	config->surface = wlc_resource_from_wl_surface_resource(surface);
-	config->resource = surface;
+	config->wl_surface_res = surface;
 	list_add(desktop_shell.backgrounds, config);
 	wl_resource_set_destructor(surface, background_surface_destructor);
 }
@@ -73,7 +73,7 @@ static void set_panel(struct wl_client *client, struct wl_resource *resource,
 	struct panel_config *config = malloc(sizeof(struct panel_config));
 	config->output = output;
 	config->surface = wlc_resource_from_wl_surface_resource(surface);
-	config->resource = surface;
+	config->wl_surface_res = surface;
 	list_add(desktop_shell.panels, config);
 	wl_resource_set_destructor(surface, panel_surface_destructor);
 	desktop_shell.panel_size = *wlc_surface_get_size(config->surface);