[retro-gtk] log: Include its header

[Adrien Plazas <aplazas src gnome org>]

commit e3bc598a5a078c08694cb650208d7d957678b372
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Fri Nov 27 13:19:39 2020 +0100

    log: Include its header
    
    This ensures retro_g_log() has its declaration and definition correctly
    linked one to the other.

 retro-gtk/retro-log.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/retro-gtk/retro-log.c b/retro-gtk/retro-log.c
index 6ec1f1ca..b6ce5099 100644
--- a/retro-gtk/retro-log.c
+++ b/retro-gtk/retro-log.c
@@ -9,6 +9,8 @@
  * Convenience functions to connect to the #RetroCore::log signal of #RetroCore.
  */
 
+#include "retro-log.h"
+
 #include "retro-core.h"
 
 /**