Parallel libtool build fixes

Serialize the use of libtool in a few places to avoid having
concurrent libtool instances in the same directory..

Change-Id: I5abaeae8f6a31cd84643b7df39c77493d198b600
Reviewed-on: http://gerrit.openafs.org/9024
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>