[patch] prevent build warnings from arlex.l and syslex.l

[John Marino]

Alan Modra wrote:
> On Tue, Apr 05, 2011 at 08:11:44PM +0200, John Marino wrote:
>> +#ifndef YY_NO_UNPUT
>>  #define YY_NO_UNPUT
>> +#endif
> 
> Is there any reason to not use this instead?
> #undef YY_NO_UNPUT
> #define YY_NO_UNPUT
> 


It's supposed to be defined by the first line "%option nounput"
If anything, the line "#undef YY_NO_UNPUT" should be deleted, however 
Nick wanted to stick with this method in case someone has a broken 
implementation of lex.

He's the one that committed the ldlex.l change on March 28.

Regards,

John