add missing trap_RealTime prototype (#4015)

code/game/g_local.h

@@ -768,6 +768,7 @@ extern	vmCvar_t	g_proxMineTimeout;
 void	trap_Printf( const char *fmt );
 void	trap_Error( const char *fmt );
 int		trap_Milliseconds( void );
+int	trap_RealTime( qtime_t *qtime );
 int		trap_Argc( void );
 void	trap_Argv( int n, char *buffer, int bufferLength );
 void	trap_Args( char *buffer, int bufferLength );