Issue #17361: Use cc from sysconfig for testing flags.
Close #15465: Document C API version macros

Mostly moving the existing macro docs over from the standard
library docs to the C API docs where they belong.

Patch by Kushal Das.
#11732: make suppress_crash_popup() work on Windows XP and Windows Server 2003.
#11732: add a new suppress_crash_popup() context manager to test.support that disables crash popups on Windows and use it in test_ctypes.
#11732: null merge with 3.2.
Fix typo in Misc/NEWS entry.
Merge typo fix in Misc/NEWS entry from 3.2.