Log message:
*: use PYTHON_VERSION instead of _PYTHON_VERSION

Log message:
*: set USE_PKG_RESOURCES for more packages

Log message:
*: bump PKGREVISION for egg.mk users

They now have a tool dependency on py-setuptools instead of a DEPENDS

Log message:
py-pip: update to 20.3.4.

20.3.4 (2021-01-23)
===================

Features
--------

- ``pip wheel`` now verifies the built wheel contains valid metadata, and can be
  installed by a subsequent ``pip install``. This can be disabled with
  ``--no-verify``. (`#9206 <https://github.com/pypa/pip/issues/9206>`_)
- Improve presentation of XMLRPC errors in pip search. (`#9315 \ 
<https://github.com/pypa/pip/issues/9315>`_)

Bug Fixes
---------

- Fixed hanging VCS subprocess calls when the VCS outputs a large amount of data
  on stderr. Restored logging of VCS errors that was inadvertently removed in pip
  20.2. (`#8876 <https://github.com/pypa/pip/issues/8876>`_)
- Fix error when an existing incompatibility is unable to be applied to a \ 
backtracked state. (`#9180 <https://github.com/pypa/pip/issues/9180>`_)
- New resolver: Discard a faulty distribution, instead of quitting outright.
  This implementation is taken from 20.2.2, with a fix that always makes the
  resolver iterate through candidates from indexes lazily, to avoid downloading
  candidates we do not need. (`#9203 \ 
<https://github.com/pypa/pip/issues/9203>`_)
- New resolver: Discard a source distribution if it fails to generate metadata,
  instead of quitting outright. This implementation is taken from 20.2.2, with a
  fix that always makes the resolver iterate through candidates from indexes
  lazily, to avoid downloading candidates we do not need. (`#9246 \ 
<https://github.com/pypa/pip/issues/9246>`_)

Vendored Libraries
------------------

- Upgrade resolvelib to 0.5.4.

Log message:
devel/py-pip20: import py-pip-20.3.3

pip is a replacement for easy_install. It uses mostly the same
techniques for finding packages, so packages that were made
easy_installable should be pip-installable as well.

pip is meant to improve on easy_install. Some of the improvements:
    * All packages are downloaded before installation.
Partially-completed installation doesn't occur as a result.
    * Care is taken to present useful output on the console.
    * The reasons for actions are kept track of. For instance, if
a package is being installed, pip keeps track of why that package
was required.
    * Error messages should be useful.
    * The code is relatively concise and cohesive, making it easier
to use programmatically.
    * Packages don't have to be installed as egg archives, they can
be installed flat (while keeping the egg metadata).
    * Native support for other version control systems (Git, Mercurial
and Bazaar)
    * Uninstallation of packages.
    * Simple to define fixed sets of requirements and reliably
reproduce a set of packages.

This is the last version that supports Python 2.x.