[arch-general] provide with version

[Christian Hesse]

Hello everybody,

I would like to replace xz 5.0.3-1 with xz-git 20111203-1. I added

provides([...] 'xz')

to the PKGBUILD, but the dependencies for libarchive (requires xz>=5.0.0) are
not met. Any chance I can fix that?
-- 
Best regards,
Chris