Add some missing includes/declarations

include/backend/drm/properties.h

@@ -2,6 +2,7 @@
 #define BACKEND_DRM_PROPERTIES_H
 
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 
 /*

include/backend/drm/renderer.h

@@ -5,8 +5,10 @@
 #include <stdint.h>
 #include <wlr/backend.h>
 #include <wlr/render/wlr_renderer.h>
+#include <wlr/util/addon.h>
 
 struct wlr_drm_backend;
+struct wlr_drm_format;
 struct wlr_drm_plane;
 struct wlr_buffer;
 

include/backend/session/session.h

@@ -1,6 +1,9 @@
 #ifndef BACKEND_SESSION_SESSION_H
 #define BACKEND_SESSION_SESSION_H
 
+#include <stdbool.h>
+
+struct wl_display;
 struct wlr_session;
 
 struct wlr_session *libseat_session_create(struct wl_display *disp);