https://github.com/artizirk/wdisplays/pull/25
https://bugs.gentoo.org/946954

--- a/subprojects/wdisplays/src/outputs.c
+++ b/subprojects/wdisplays/src/outputs.c
@@ -526,7 +526,7 @@
 static const struct zwlr_output_manager_v1_listener output_manager_listener = {
   .head = output_manager_handle_head,
   .done = output_manager_handle_done,
-  .finished = noop,
+  .finished = (void (*)(void *, struct zwlr_output_manager_v1 *))noop,
 };
 static void registry_handle_global(void *data, struct wl_registry *registry,
     uint32_t name, const char *interface, uint32_t version) {
@@ -553,7 +553,7 @@
 
 static const struct wl_registry_listener registry_listener = {
   .global = registry_handle_global,
-  .global_remove = noop,
+  .global_remove = (void (*)(void *, struct wl_registry *, uint32_t))noop,
 };
 
 void wd_add_output_management_listener(struct wd_state *state, struct
@@ -603,10 +603,10 @@
 
 static const struct zxdg_output_v1_listener output_listener = {
   .logical_position = output_logical_position,
-  .logical_size = noop,
-  .done = noop,
+  .logical_size = (void (*)(void *, struct zxdg_output_v1 *, int32_t,  int32_t))noop,
+  .done = (void (*)(void *, struct zxdg_output_v1 *))noop,
   .name = output_name,
-  .description = noop
+  .description = (void (*)(void *, struct zxdg_output_v1 *, const char *))noop
 };
 
 void wd_add_output(struct wd_state *state, struct wl_output *wl_output,