Re: RFC: build: be robust to missing flex

[Stefano Lattarini]

On 03/27/2012 04:16 PM, Akim Demaille wrote:
> 
> [BIG SNIP]
>
> diff --git a/configure.ac b/configure.ac
> index 622da5d..5c97683 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -110,6 +110,9 @@ AC_SUBST([YACC_LIBRARY])
>  
>  # Checks for programs.
>  AC_PROG_LEX
> +if $LEX --version 2>/dev/null | $EGREP 'f?lex 2\.5\.3' >/dev/null; then :; 
> else
> +  AC_MSG_ERROR([flex 2.5.3* is required])
> +fi
>
I think the best fix in the long term would be to enhance AC_PROG_LEX to set
a variable telling whether $LEX is flex or not (similarly to what is done by
AC_PROG_CC etc.).  The Bison's configure could simply use this variable to
determine whether a good-enough flex has been found.

Would you think it worthwhile to submit a patch to Autoconf before 2.69 gets
released?

Regards,
  Stefano