qmqtool is just a lightweight perl script.  But because we pretend
to be fancy, we have an install process:

1. run ./configure
   optional arguments to configure are:
    --perl=PERL		full path to perl (e.g. /usr/local/bin/perl)
    --destdir=DIR		directory to install qmqtool (e.g. /usr/local/script)
    --qmaildir=DIR	directory qmail is locted (e.g. /var/qmail)
    --help				show help message
2. run make
3. run make install