command-line option values processing system

 App::Options combines command-line arguments, environment variables, option
 files, and program defaults to produce a hash of option values.
 .
 Furthermore, its special treatment of the "perlinc" option facilitates the
 inclusion ("use") of application-specific perl modules from special places
 to enable the installation of multiple versions of an application on the same
 system (i.e. /usr/myproduct/version).