Milter-greylist

If I have any typos in the configuration, milter-greylist aborts
startup and logs a message like this:

   config error at line 1427: syntax error
   end Sun Aug 11 06:20:38 MSK 2013: done.

I would like this error to also display the offending line itself,
in order to ease administrative debugging.

I've traced it to 448:conf_lex.l yyerror() routine, but this is
not mentioned anywhere else in the code. I am not familiar with
lex beyond monkey-cloning a few constructs recently to define new
config variables; so I'd like to propose this (probably simple)
RFE to someone who can implement it :)

Thanks,
//Jim