in an infinite loop.  Patch by Xavier de Gaye.

Issue #24891: Fix a race condition at Python startup if the file descriptor
of stdin (0), stdout (1) or stderr (2) is closed while Python is creating
sys.stdin, sys.stdout and sys.stderr objects. These attributes are now set
to None if the creation of the object failed, instead of raising an OSError
exception. Initial patch written by Marco Paolini.

Don't download sources that won't be used.

Issue #24989

set beyond size.  Based on patch by John Leitch.

This modifies the behavior of the '-e' flag to PCbuild\build.bat: when '-e'
is not supplied, no attempt will be made to build extension modules that
require external libraries, even if the external libraries are present.

Also adds '--no-<module>' flags to PCbuild\build.bat, where '<module>' is
one of 'ssl', 'tkinter', or 'bsddb', to allow skipping just those modules
(if '-e' is given).

This makes it possible to pass more than 4 tests by name through
Tools\buildbot\test.bat

set beyond size.  Based on patch by John Leitch.

The ICC compiler doesn't seem to support defined() in macro expansion. Example
of warning:

warning #3199: "defined" is always false in a macro expansion in Microsoft mode