Split up libtool support into LWP and pthread

Split up libtool support into LWP and pthread

Currently, the type of library you build is determined by whether
the library is build in a pthread, or an lwp build directory. However,
this prevents building an LWP library in a directory that builds
pthreaded clients and servers.

As we want to continue to provide LWP libraries for backwards
compatibility, but move over to pthreaded binaries, this causes
some issues.

So, split up the libtool logic, so we have Makefile.libtool, which
you include if you want to build a pthreaded libtool library, and
Makefile.lwptool, for building a library which supports LWP and
pthreaded use. These only affect how .lo files are built - so the
.o files used for non-library objects are managed with the
Makefile.pthread and Makefile.lwp includes as before.

Change-Id: Ib1af48342253230abab9056eb15a3f79bd77a6de
Reviewed-on: http://gerrit.openafs.org/8126
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>