macros into our namespace and limit use to headers. A subsequent
round will add macros to separately handle forward declarations
of variables from declaration of function prototypes. The last
round will add additional macros for declaring actual variables and
functions.
r/w locks and thread pools. Hide internal structures (using
pthread'ish technics). Place common code in threads.c. Move
no-thread code to thr_stub.c. Move thread pool code to tpool.c.
Removed setconcurrency call from initializer, added 'concurrency'
directive to slapd. Tested code under pthreads, pth, and no-threads.
