internal/wayland: improve error handling

Note: wl_registry_add_listener is undocumented everywhere. Its implementation calls wl_proxy_add_listener which returns 0 on success or -1 on failure.
Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/wayland/wayland-client-helper.h

@@ -1,6 +1,22 @@
-#include <stdint.h>
+typedef enum {
+  HAKUREI_WAYLAND_SUCCESS,
+  /* wl_display_connect_to_fd failed, errno */
+  HAKUREI_WAYLAND_CONNECT,
+  /* wl_registry_add_listener failed, errno */
+  HAKUREI_WAYLAND_LISTENER,
+  /* wl_display_roundtrip failed, errno */
+  HAKUREI_WAYLAND_ROUNDTRIP,
+  /* compositor does not implement wp_security_context_v1 */
+  HAKUREI_WAYLAND_NOT_AVAIL,
+  /* socket failed, errno */
+  HAKUREI_WAYLAND_SOCKET,
+  /* bind failed, errno */
+  HAKUREI_WAYLAND_BIND,
+  /* listen failed, errno */
+  HAKUREI_WAYLAND_LISTEN,
+} hakurei_wayland_res;
 
-int32_t hakurei_bind_wayland_fd(
+hakurei_wayland_res hakurei_bind_wayland_fd(
     char *socket_path,
     int fd,
     const char *app_id,