Story

As someone who bootstraps Python packages in Fedora or EPEL,
I want that rpmautospec has a minimal footprint of hard external dependencies,
so that I have little trouble bootstrapping aches.

Acceptance Criteria

• A minimal adapter to libgit2 exists which
  • … uses ctypes to call into libgit2
  • … covers the functionality used by rpmautospec during runtime and in tests
  • … mimics the pygit2 API as closely as possible, so it makes no material difference if it or pygit2 is used
  • … prefers known versions of libgit2 before degrading to unknown newer ones
• A compatibility layer exists which attempts to load pygit2 and upon failure falls back to the minimal adapter
• CI tests are adapted so the testsuite is run with both pygit2 and the minimal adapter
• Licensing between rpmautospec itself (MIT) and rpmautospec.minigit2 (partially derived from pygit2, so GPLv2 with licensing exception) is clarified.

Background

• Dogfooding all around – rpmautospec, pygit2, cffi all use %autorelease/%autochangelog. This is a nice catch-22 when bootstrapping a new Python version.
• The cffi package was unavailable for a long time in the ramp up to Python 3.13.