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

Comece em pyexpat.c, onde as macros de versão do Expat e as APIs de versão em tempo de execução são expostas. Siga as definições existentes de VERSION_INFO e version_info e, em seguida, verifique se a versão do build é exposta separadamente e se version_info tem comportamento de tupla nomeada. Verifique os testes da API do pyexpat, se disponíveis, e confirme que ambas as versões são informadas corretamente quando diferem.