diff --git a/src/external/mud/src/mud.h b/src/external/mud/src/mud.h
index acf6bdee..bf7a3c30 100644
--- a/src/external/mud/src/mud.h
+++ b/src/external/mud/src/mud.h
@@ -204,7 +204,7 @@ typedef UINT32                  BOOL;
 #define strdup( s )			strcpy((char*)malloc(strlen(s)+1),s)
 #endif /* vms || mips&&!sgi */
 /*#endif */
-typedef int (*MUD_PROC)();
+typedef int (*MUD_PROC)(...);
 
 typedef enum {
     MUD_ENCODE = 0,