Make the mutex static initializers look more like the one for condition variables. Cosmetic.
Make the mutex static initializers look more like the one for
condition variables. Cosmetic.

Explicitly compare against PTHREAD_MUTEX_INITIALIZER. We shouldn't
encourage calls to the mutex functions with null pointers to mutexes.

Approved by:	re/jhb

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase