sem_unlink calls to delete those semaphore files.

This is for consistency with imitation file objects like StringIO and BytesIO.

This commit also adds a few tests, where they were lacking for concerned
methods.

in 2.7 alpha 1)

default.

TarFile's errorlevel argument controls how errors are
handled that occur during extraction. There are three
possible levels 0, 1 and 2. If errorlevel is set to 1 or 2
fatal errors (e.g. a full filesystem) are raised as
exceptions. If it is set to 0, which is the default value,
extraction errors are suppressed, and error messages are
written to the debug log instead. But, if the debug log is
not activated, which is the default as well, all these
errors go unnoticed.

The original intention was to imitate GNU tar which tries
to extract as many members as possible instead of stopping
on the first error. It turns out that this is no good
default behaviour for a tar library. This patch simply
changes the default value for the errorlevel argument from
0 to 1, so that fatal extraction errors are raised as
EnvironmentError exceptions.

in the middle of populating a tuple.  Patch by Florent Xicluna.

(note: no NEWS entry for trunk since the bug was introduced in 2.7/3.1)

equivalent[*] check that doesn't produce compiler warnings about a 'x < 0'
check on an unsigned type.

[*] it's equivalent for inputs of type size_t or Py_ssize_t, or any smaller
unsigned or signed integer type.

on OSX. Without this patch it wasn't possible after all
to compile extensions on OSX 10.6 with the binary
installer unless the user had installed the (non-default)
10.4u SDK.

missing proper end-of-line termination.  Patch and tests by
Scott Dial.  The new tests include a test harness which will
make it easier to add additional tests.

Diagnosis and original patch by Florent Xicluna (flox).

an i386 based machine, but should only be active when compiling the x86 part of
the universal binary.

wrong parameter types.  Patch by Victor Stinner.

Issue #7457: added a read_pkg_file method to distutils.dist.DistributionMetadata so we can read back PKG-INFO files