mail500 should be run-time configurable (ITS#93)

[dustin@spy.net]

Full_Name: Dustin Sallings
Version: dev
OS: SunOS 4.1.4, Solaris 2.6, IRIX 6.2, NetBSD 1.3.*, OpenBSD 2.3, etc...
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (209.185.98.78)


mail500 should not require source code modification and recompilation to change
the
way it's configured.  It's currently difficult for anyone not familiar with the
C
API, or without the source ready to build on his/her machine to change the
behavior
of mail500.