Issue #18259: Declare sethostname in socketmodule.c for AIX
merge heads
fixed libffi on PPC without __NO_FPRS__
ISO C90 forbids mixed declarations and code
Issue #18202: Fix minor bugs and cleanup test_coding.py.
fix libffi build on AIX (closes #18248)
Tweak programming faq examples so that it (mostly) passes doctest.

The exception is the import related questions at the end, which
need to be rewritten anyway.