For those who want/need to install a Perl app or extension without perturbing the default perl library tree.
1. Disambiguating the existing libs from your libs (for testing perhaps)
2. Not wanting to or not having rights to login as a supervisor (or as a user with admin rights)
3. Prefer to encapsulate resources in a local tree (easy to move / remove, or whatever reason)
4. Yet another reason I may have overlooked
lessons learned are:
a. utilize the 'LIB= argument when creating your makefile
example: perl Makefile.PL LIB=/users/george/myperlprogram/lib/
b. avoid the temptation to tweak @INC (purported to make use of that library location)
...and instead utilize 'use lib'
example: in MathServer.pm and MathClient.pm (for my projects purposes)
use lib MathSystem
c. then we discovered an even better way is:
example: perl Makefile.PL LIB="./lib/" ## ie. use a relative path...
which makes it OK to :
use MathSystem ## no need for 'use lib MathSystem'
Resulting benefits: No need for admin rights to install, no need to push a path onto @INC at runtime