Fix ./configure to provide a more sensible default for
MACOSX_DEPLOYMENT_TARGET. Currently the default is the minimum OS X level
that supports the universal arch option, typically 10.4, even when no
universalsdk is selected. This causes various desirable features that
depend on later OS X versions, like libedit readline support, to be
omitted from the build. A more complete solution would take into account
the SDK that is being used and better tailor the universal arch options.
For now, change the existing tests to only apply to build systems of 10.5
and earlier; for 10.6 and later, use the build system version as the
default deployment target if the MACOSX_DEPLOYMENT_TARGET environment
variable is not provided.

Skip test in freebsd entirely - Kernel bug in freebsd7/8/9 - #10142: Support for SEEK_HOLE/SEEK_DATA

of os.listdir().

to using signal.alarm(1) instead of signal.setitimer(signal.ITIMER_REAL, 0.1).

This is an attempt to see if this change is what caused the ubuntu arm buildbot
to hang in test_io's test_interrupted_write_retry_text.
Discussion in Issue #12268.

to using signal.alarm(1) instead of signal.setitimer(signal.ITIMER_REAL, 0.1).

This is an attempt to see if this change is what caused the ubuntu arm buildbot
to hang in test_io's test_interrupted_write_retry_text.
Discussion in Issue #12268.

Fixes issue 15039: namespace packages are no longer imported in preference to modules of the same name.

plain tuple to a collections.namedtuple.

leads to failures in successive 64-bit/32-bit builds in the same shell window.