Add structured version info for pyexpat

Feature or enhancement

pyexpat.EXPAT_VERSION (from XML_ExpatVersion()) and pyexpat.version_info (from XML_ExpatVersionInfo()) describe the Expat library loaded at runtime: both functions are compiled into libexpat from its XML_MAJOR_VERSION, XML_MINOR_VERSION and XML_MICRO_VERSION macros. The same macros evaluated in pyexpat.c give the version of the headers the module was built against, which is what the #if XML_COMBINED_VERSION >= ... checks in the module depend on. The two can differ when a system libexpat is used. The build-time version is not exposed to Python; it can only be inferred from which parser methods exist.

Add pyexpat.VERSION_INFO for the build-time version, and make pyexpat.version_info a named tuple.

Linked PRs

• gh-157474

Commencez dans pyexpat.c, où sont exposées les macros de version d’Expat et les API de version à l’exécution. Suivez les définitions existantes de VERSION_INFO et version_info, puis vérifiez que la version au moment de la compilation est exposée séparément et que version_info se comporte comme un named tuple. Consultez les tests de l’API pyexpat, s’ils sont disponibles, et confirmez que les deux versions sont correctement signalées lorsqu’elles diffèrent.