A 2.5 patch would not be accepted; there won't be any new features 
for 2.5 , and new port would be a new feature.

Procedurally, are you willing to support a QNX port for the coming years
(say, 5 years)? Otherwise, there is little point in accepting such a
port if there is no maintenance to it.

In general, I would prefer if the things this patch corrects were
detected through autoconf, rather than being hard-coded by system name.

For example, if using TCGETA and TCSETA requires sys/termio.h to be
included, there should be an autoconf test that checks whether TCGETA
can be used without sys/termio.h being included, and, if not, defines a
macro that says so.

However, I don't understand this entire point: What do you mean by
"using TCGETA requires that struct termio be defined"? How is TCGETA
defined to produce such a dependency? TCGETA is a constant, right?

py_curses.h: Can you explain what stdlib.h and ncurses.h define to guard
definition of wchar_t? Why do you have two cases: _XOPEN_SOURCE_EXTENDED
and not? Surely only one of them applies to Python. Can you come up with
an autoconf test that checks whether stdlib.h defines wchar_t and has a
guard and that ncurses also defines wchar_t and fails to compile if it
is guarded differently?

stack size: it would be good if it was sized by default such that the
default recursion limit won't cause crashes (but proper stack
overflows). If 2MiB are sufficient for the default recursion limit, it's
fine - otherwise, either reserver more stack, or reduce the default
recursion limit.

malloc_closure should use _SC_PAGESIZE when it is defined, and fall back
to getpagesize only otherwise.