contrib: add ParseTrace prototype to parser skeleton

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

contrib/lempar.c

@@ -205,6 +205,7 @@ static char *yyTracePrompt = 0;
 ** Outputs:
 ** None.
 */
+void ParseTrace(FILE *TraceFILE, char *zTracePrompt);
 void ParseTrace(FILE *TraceFILE, char *zTracePrompt){
   yyTraceFILE = TraceFILE;
   yyTracePrompt = zTracePrompt;