Patch by Sandro Tosi.

Patch by Sandro Tosi.

in libmpdec to prevent undefined behavior if an invalid context is used. This
cannot occur for the _decimal module since user input for the context is
validated.

PyFloatObjects are now allocated using PyObject_MALLOC like all other
internal types, but maintain a limited freelist of objects at hand for
performance.  This will result in more consistent memory usage by Python.

Removed the useless explanation of the Element data structure that started the
documentation page. Instead, the documentation now starts with a brief tutorial
skimming some of the capabilities of the module. The tutorial can be followed
by additional topic-specific sections (such as XPath support), and eventually
by a reference that goes over the module's classes and functions, as usual.

Patch by Roger Serwy.

Unlike the other facilities, we don't use a fallback for AUTHPRIV if it
doesn't exist.  Because it is intended for logging sensitive log messages, it
is better that a program trying to log such messages fail than that it log
them insecurely.

Initial patch by Federico Reghenzani.

clock_gettime(CLOCK_REALTIME) has a better resolution than gettimeofday().
time.time() falls back on gettimeofday() (and then on other functions) on
error.

And call mach_absolute_time() after mach_timebase_info().

These functions simplify the usage of static constant Unicode strings.
Generalize the usage of _Py_Identifier in ceval.c and typeobject.c.

floattime() must not raise an error if the current time is 1970.1.1 at 00:00.