On POSIX systems, the pkg-config (``.pc``) filenames now include the ABI
flags, which may include debug ("d") and free-threaded ("t").  For example:
* ``python-3.14.pc`` (default, non-debug build)
* ``python-3.14d.pc`` (default, debug build)
* ``python-3.14t.pc`` (free-threaded build)
