requiring yacc to build xkbcomp

[Julien Cristau]

On Wed, Jun  2, 2010 at 17:08:44 -0700, Gaetan Nadon wrote:

>  configure.ac |    2 ++
>  1 file changed, 2 insertions(+)
> 
> New commits:
> commit 07cc4d60dea2b4c947fed45b082edae4a53b186a
> Author: Gaetan Nadon <memsize at videotron.ca>
> Date:   Wed Jun 2 15:23:58 2010 -0400
> 
>     config: add check for yacc to insure it is installed #27973
>     
>     Unlike other macros AC_PROG_YACC sets the YACC variable to "yacc"
>     as a last resort, even if no programs have been found. Improve error
>     checking by issuing an error message if yacc is not found. The module
>     cannot build anyway.
>     
>     Reported-by: Peter Hutterer <peter.hutterer at who-t.net>
>     Reviewed-by: Peter Hutterer <peter.hutterer at who-t.net>
>     Signed-off-by: Gaetan Nadon <memsize at videotron.ca>
> 
When building from tarball, yacc isn't needed because xkbparse.c is
shipped.

Cheers,
Julien