like to add a configure option.

[Sri Ramkrishna]

In the 1.0 release, I'd like to be able to specify from configure what
my mail spool file is.  I had changed the mail spool to /usr/spool/mail
but kept /var/spool/mail around.  

This should be a simple change.  I don't know autoconf very well, otherwise
I would have sent a patch.  Would this be possible?

        sri