[PATCH util-macros] Add XORG_WITH_XMLTO to factorize xmlto tests.

[Julien Cristau]

On Tue, Jan 12, 2010 at 19:08:49 -0500, Gaetan Nadon wrote:

>  Changed my mind about 'yes' + 'missing xmlto' = error. Not for this macro to decide. WARN instead.

When we get an explicit command line argument, I think it needs to
either be obeyed or lead to an error.  A warning is just going to go
unnoticed, so this is just ignoring the user's request.

Thanks for considering,
Julien