setuptools: Update to 9.1
Some progress for the Pidgin++ package.

* The configure script is not suitable for building Pidgin on Windows, we need
  to use the static makefiles instead, and configure the build to seek for the
  dependencies in MSYS2 itself, not in the development root described by
  https://developer.pidgin.im/wiki/BuildingWinPidgin.

* The package is not split into the pidgin++, libpurple and finch packages
  anymore, this can be done later.

* The latest Bazaar revision is used instead of a tarball.

* Source code has been refactored.

Currently the build fails at SASL stuff or something. However, the archetype for
the PKGBUILD is ready, it's now just a matter of fixing these specific issues.
First build of the pidgin++ package.

* Add some makedepends.

* Use a Bazaar branch targeted at building with makepkg.

* Use the winbuild.sh script instead of direct calls to make.

  The winbuild and pidgin-windev scripts have been updated to allow creating a
  minimal environment only with the dependencies that are missing in MSYS2 or
  that for some reason cannot work. For example, the GTK+ from MSYS2 is used
  instead of downloading one manually, but WinSparkle lacks a package in MSYS2
  and is thus downloaded.

* Some other small changes.
Add todo list for the pidgin++ package.
Improvements for the pidgin++ package.

* Remove make configuration since it has been implemented in Pidgin++.
* Some code refactoring.
More progress for the pidgin++ package.

* Disable the Sametime and SILC protocols.
  Pidgin++ has been updated to support this and also use the TCL library from
  MSYS2. Now the remaining binary downloads are pidgin-inst-deps and WinSparkle.

* Install EasyOptions.

* Add pidgin as a conflicting package.

* Fix missing checkout for the Bazaar branch.

* Update makedepends and other small changes.
More progress for the pidgin++ package.

* Use the new --pkgbuild option from winbuild script.
  This will handle disabling of binary downloads so that a purely source-based
  package can be created. There is currently one remaining binary dependency,
  WinSparkle.

* Fix customization of the GTK+ runtime.
  This is done when creating the GTK+ runtime from Fedora servers and is now
  replicated into the PKGBUILD so that the MSYS2 GTK+ can also have the
  customizations applied.

* Other minor changes.
Update the todo list.
Updates for the pidgin++ package.

* Remove list of contributors since their work is not present anymore.
* Remove call to pidgin-windev --prepare since this is not needed anymore.
* Remove depends and optdepends, and update makedepends.
* Update the Bazaar repository URL.
* Other small changes.
Update the todo list.
Fix the git suffix in pidgin++ package.
Remove the rev prefix from the pidgin++ package version.