add -D rsyslogd option to enable config parser debug mode

ChangeLog

@@ -1,5 +1,6 @@
 ----------------------------------------------------------------------------
 Version 7.2.1  [v7-stable] 2012-10-??
+- added -D rsyslogd option to enable config parser debug mode
 - improved syntax error messages by outputting the error token
 - the rsyslog core now suspeneds actions after 10 failures in a row
   This was former the case after 1,000 failures and could cause rsyslog

tools/rsyslogd.8

@@ -10,6 +10,7 @@ rsyslogd \- reliable and extended syslogd
 .RB [ " \-6 " ]
 .RB [ " \-A " ]
 .RB [ " \-d " ]
+.RB [ " \-D " ]
 .RB [ " \-f "
 .I config file
 ]
@@ -124,6 +125,11 @@ This option has been obsoleted and has no function any longer. It is still
 accepted in order not to break existing scripts. However, future versions
 may not support it.
 .TP
+.B "\-D"
+Runs the Bison config parser in debug mode. This may help when hard to find
+syntax errors are reported. Please note that the output generated is deeply
+.TP
+technical and orignally targeted towards developers.
 .B "\-d"
 Turns on debug mode.  Using this the daemon will not proceed a 
 .BR fork (2)

tools/syslogd.c

@@ -93,6 +93,8 @@
 #include <zlib.h>
 #endif
 
+extern int yydebug; /* interface to flex */
+
 #include <netdb.h>
 
 #include "pidfile.h"
@@ -1830,7 +1832,7 @@ int realMain(int argc, char **argv)
 	 * of other options, we do this during the inital option processing.
 	 * rgerhards, 2008-04-04
 	 */
-	while((ch = getopt(argc, argv, "46a:Ac:def:g:hi:l:m:M:nN:op:qQr::s:t:T:u:vwx")) != EOF) {
+	while((ch = getopt(argc, argv, "46a:Ac:dDef:g:hi:l:m:M:nN:op:qQr::s:t:T:u:vwx")) != EOF) {
 		switch((char)ch) {
                 case '4':
                 case '6':
@@ -1863,6 +1865,10 @@ int realMain(int argc, char **argv)
 		case 'd': /* debug - must be handled now, so that debug is active during init! */
 			debugging_on = 1;
 			Debug = 1;
+			yydebug = 1;
+			break;
+		case 'D': /* BISON debug */
+			yydebug = 1;
 			break;
 		case 'e':		/* log every message (no repeat message supression) */
 			bEOptionWasGiven = 1;