Installation location of Perl and Python modules

I need a user poll regarding a PostgreSQL 7.2 development issue.  In what
follows I only speak of Perl, but you may substitute Python almost
everywhere.

There have been complaints that the Perl module automatically installs
itself under /usr/lib/perl5, even if the installer is not the root user
and even if he specified a different --prefix.  It would naturally be
beneficial if users without root access, or those that don't want to
overwrite their system installation, had the chance to install the Perl
module somewhere, somehow.

The question is which of the following installation schemes would be
useful to provide, and which one should be the default.

1. Install it under /usr/lib/perl5 (or whatever the default location).

2. Install it under $prefix/lib/perl5, where $prefix is what is chosen for
   PostgreSQL.  This would improve the likelyhood of write access to the
   location, give you a perlish layout, and (usually) fall back to the
   default if you specify --prefix=/usr.  It might also be rather compliant
   to some file system standard.

3. Install it under $prefix/lib/postgresql.  This would guarantee
   write access, and enhance the consistency with the GNU-style configure
   process.  It could also be compliant to some file system standard.

4. Provide an option to freely choose the location.  But keep in mind that
   "free to choose" also means "inconsistent" and "easy to get lost".

Anything but #1 will require setting the environment variable PERLLIB or
use -I flags or some such.  This is not inconsistent with the requirement
to set PATH, MANPATH, etc., at least if Perl were to search something in
/usr/local by default.

Currently, we have #1 as the default and incomplete, hidden support for
#3.  If we were to start in a green field we might make #2 the default
with an option for #4.

The questions are, "what would users expect" and "what would users like"?

--
Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter