--- surf.c
+++ surf.c
@@ -217,6 +217,7 @@ static void togglefullscreen(Client *c, const Arg *a);
 static void togglecookiepolicy(Client *c, const Arg *a);
 static void toggleinspector(Client *c, const Arg *a);
 static void find(Client *c, const Arg *a);
+static void playexternal(Client *c, const Arg *a);
 
 /* Buttons */
 static void clicknavigate(Client *c, const Arg *a, WebKitHitTestResult *h);