lwp: Build a pthreaded compat library with libtool

lwp: Build a pthreaded compat library with libtool

The majority of the LWP directory isn't used by pthreaded applications.
However, there are three files - fasttime.c, lock.c and waitkey.c which
are used within pthreaded code.

Eventually, these should live somewhere other than the LWP directory.
For now, just build a small pthreaded library to hold them, so we
can finish up with the libtool work before considering how to move
this code elsewhere.

Change-Id: I66281f7cd838c048fd982bbd0f756a16a10862d1
Reviewed-on: http://gerrit.openafs.org/8069
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>