automake/autoconf

[jerryyhom at gmail.com]

I am working on a portfile for libressl.  I set some options like so:

use_autoconf    yes
use_automake    yes

but 'port lint --nitpick' warned that port dependencies are listed 
multiple times.  I commented out one and successfully built the package. 
  Then I tried reversing the commented option and also successfully 
built the package.

As they both seem to do the correct thing, what is the difference 
between these options?  Is one preferred?  Perhaps their difference 
could be clarified in the Guide.  Thanks!