Issue #13812: When a multiprocessing Process child raises an exception, flush stderr after printing the exception traceback.

Closes #13859: Replaced reference to StandardError with reference to Exception. Thanks to Matt Joiner for spotting this and submitting a patch.

(rather than `-m test.regrtest`)

Issue #11235: Fix OverflowError when trying to import a source file whose modification time doesn't fit in a 32-bit timestamp.

target's type (file or directory).  The detection was buggy and made the
call non-atomic (therefore prone to race conditions).

an actual function.

"oops" while rearranging the #defines.

Many lack readdir64, use readdir.  Only use readdir64 on solaris where
it is required to work around a solaris bug.

suboptimal by closing all possible file descriptors rather than just
the open ones in the child process before exec().

It now closes only the open fds when it is possible to safely determine what
those are.

Issue #12922: fix the TextIOBase documentation to include a description of seek() and tell() methods.