-DNO_THREADS, select(), signals

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

As noted a couple in a couple of different threads, slapd
would benefit greatly from threaded I/O management system
(It currently uses a select-based I/O management system).
The integration of the thread-based processing system
and the select-based I/O system has been problematic.
Though we have worked out most of the problems, new issues
(multiple listeners, TLS, NT, thread pools) will cause
further stress to be added to this design mismatch.

I would like to reimplement our select-based connection
management to use threaded implementation (using per-socket
threads).  This will eliminate the dependency upon select(),
signals, and greatly simplify I/O and operation thread
management.

However, the expense is -DNO_THREADS.

Any heartburn if -DNO_THREADS support is dropped?