python: improved cross-compiling setting ac_cv_buggy_getaddrinfo=no

Note

Only cross-checked the correctness against a native build using glibc!
Other libc implementations like musl need to be checked too!

Failure when running configure
----------------------------------------------------------------------
checking getaddrinfo bug... yes
Fatal: You must get working getaddrinfo() function.
       or you can specify "--disable-ipv6"
----------------------------------------------------------------------
python: fixed cross-compiling by setting ac_cv_file__dev_ptmx=yes

Note

We can safely assume that the runtime system will have /dev/ptmx!
Strangely enough on a native build I have /dev/ptmx didn't got detected,
which is most probably an issue with our sandbox and needs some more
observation!
python: fixed cross-compiling setting ac_cv_file__dev_ptc=no

There is no /dev/ptc on Linux because it is AIX specific.