Add an LWP version of the hcrypto library

Add an LWP version of the hcrypto library

hcrypto uses a single pthread mutex, which is only required when
we're running in a pthreaded world (in a cooperative threading world
such as LWP, there's no way that two processes can both access the
Fortuna PRNG at the same time)

So, build an LWP version of hcrypto which just disables the mutexes.

Change-Id: I0b894cfa0d16ba6d16544a4d725191c965ac6e50
Reviewed-on: http://gerrit.openafs.org/2833
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>