package/xorriso: fix to use the system xattr header

package/xorriso: fix to use the system xattr header

We don't carry a git-formatted patch, because upstream is in fact a
collection of git trees, while the release tarball is an aggregate
of those repositories. Thus, the layout is different between the
tarball and the SCM...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Steve Kenton <skenton@ou.edu>
[Thomas:
 - add host-pkgconf as a dependency of host-xorriso, since it's needed
   for autoreconf to work
 - drop HOST_XORRISO_AUTORECONF = YES, since it's implied by
   XORRISO_AUTORECONF = YES.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>