+ where is a Perl module installed, e.g.
  perl -MPCP::PMDA -e 'print $INC{"PCP/PMDA.pm"} . "\n"'

+ developer install (new/updated bits over the top of an existing PCP
  Perl installation) ... in each subdir, e.g. MMV
  $ make
  $ sudo make -f Makefile pure_perl_install
