autoconf: updates and cleanup

autoconf: updates and cleanup

Update autoconf macros to their modern equivalents, according to what
the 'autoupdate' tool does. While we're here, remove automake references
that aren't being used, and remove the obsolete AC_PROG_LIBTOOL in favor
of AFS_LT_INIT.

Reviewed-on: https://gerrit.openafs.org/12199
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit 4706854f57043c8393baa922dd1974176e110a19)

Change-Id: I9b3b8a15ac73484f60d16448abd8cce2e0334201
Reviewed-on: https://gerrit.openafs.org/13480
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Tested-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>