Make.conf variables

[Matthew Smith]

    Quick question/observation:  as I peruse /etc/defaults/make.conf for 
variables I can include in /etc/make.conf to slim down my system, I 
notice that some variables are listed as "NO_*", while others are listed 
as "NO*" (no underscore).  For example, NO_SENDMAIL vs  NOPERL.  Is 
there a reason for this seeming inconsistency?  Or is it just that no 
one has spent the time on it?  Obviously, there are no technical 
difficulties with this -- it just is a little harder for me to remember 
the name of the variables as I type them into make.conf.

-Matt