Add the msys-docbook package

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
Add msys-libxml2 package

The existing upstream package makes xmlcatalog (and xsltproc) crash for
some reason.

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>