Squash a frightening number of warnings from XBSA-related code

Squash a frightening number of warnings from XBSA-related code

Mostly missing prototypes and mismatched format strings, but also some
more disturbing bugs.

Reviewed-on: http://gerrit.openafs.org/11960
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Daria Brashear <shadow@your-file-system.com>
(cherry picked from commit 540050bbc893416fbd075ed5e349abaa5baaeba1)

Change-Id: I45711fb064490a51a5ecf316b89073dbfabab55b
Reviewed-on: https://gerrit.openafs.org/12357
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>