Motivated by deprecation of distutils, I like to move more logic and checks from setup.py into configure.ac. Eventually I like to get rid of setup.py. The file contains a bunch of complicated checks and macOS-specific adjustments that I cannot verify on Linux.


1) socketmodule setup defines __APPLE_USE_RFC_3542 https://github.com/python/cpython/blob/v3.11.0a2/setup.py#L1229 Can we move the define into the __APPLE__ block of socketmodule.c?


2) -Wl,-search_paths_first linker arg, e.g. https://github.com/python/cpython/blob/v3.11.0a2/setup.py#L1616  Would it be safe to make the option default for all core extensions on $ac_sys_system = Darwin? We could add it to PY_CORE_LDFLAGS or add a new Makefile variable for core extensions.


3) detect_dbm_gdbm has about 200 lines of complicated code to detect old to ancient versions of Berkeley DB (libdb), https://github.com/python/cpython/blob/v3.11.0a2/setup.py#L1233 . Can I remove support for libdb-3 / libdb-4 and only support libdb-5 in standard locations? libdb-5.3 has been around for over a decade.

Note: libdb, gdbm, ndbm, and gdbm-compat don't provide pkg-config .pc files. We cannot use pkg-config to detect them.


4) sqlite's setup https://github.com/python/cpython/blob/v3.11.0a2/setup.py#L1531 does extra work to search for header and library files in non-standard locations. Can we replace the code with pkg-config checks in configure.ac with a fallback to AC_CHECK_LIB() and AC_CHECK_HEADERS()?


5) zlib's setup code https://github.com/python/cpython/blob/v3.11.0a2/setup.py#L1661 has a check for a CVE from 2002 (!). I think we can safely assume that everybody has upgraded to a fixed version. The check is mixed with macOS specific code.