fixed compilation on more strict compilers

svn-id: r4320

1 files changed, 1 insertions, 1 deletions

diff --git a/system.h b/system.h
index 59088d62e6..5a8855d1fa 100644
--- a/system.h
+++ b/system.h
@@ -137,7 +137,7 @@ public:
 	virtual void update_cdrom() = 0;
 
 	// Add a new callback timer
-	virtual void set_timer(int timer, void* callback) = 0;
+	virtual void set_timer(int timer, int (*callback)(int)) = 0;
 
 	// Quit
 	virtual void quit() = 0;