Minor BSD fixes for Hugs Aug03

The first patch to prelude.h avoids loads of gratuitious warnings about using malloc.h (which is deprecated). The second patch to configure.in caters for FreeBSDs different pthread-flags. (Perhaps it's better to let the user supply the correct CFLAGS for threads?) I think both patches apply to OpenBSD and NetBSD as well. Regards, Volker (cc: Mr. OpenBSD) -- Volker Stolz * http://www-i2.informatik.rwth-aachen.de/stolz/ * PGP * S/MIME