* Add _Py_GetLocaleconvNumeric() function: decode decimal_point and
  thousands_sep fields of localeconv() from the LC_NUMERIC encoding,
  rather than decoding from the LC_CTYPE encoding.
* Modify locale.localeconv() and "n" formatter of str.format() (for
  int, float and complex to use _Py_GetLocaleconvNumeric()
  internally.

Patch by Pablo.

* Add Py_UNREACHABLE() as an alias to abort().
* Use Py_UNREACHABLE() instead of assert(0)
* Convert more unreachable code to use Py_UNREACHABLE()
* Document Py_UNREACHABLE() and a few other macros.

numbers.  Patch by Stefan Behnel.

Close issue #8931: Make alternate formatting for 'c' raise an exception. Patch by Torsten Landschoff.

Closed issue #8931: Make alternate formatting for 'c' raise an exception. Patch by Torsten Landschoff.

error messages and comments.

complex.__format__().

compare two Unicode kinds

when possible

 - Use _PyLong_FormatWriter() instead of formatlong() when possible, to avoid
   a temporary buffer
 - Enable the fast path when width is smaller or equals to the length,
   and when the precision is bigger or equals to the length
 - Add unit tests!
 - formatlong() uses PyUnicode_Resize() instead of _PyUnicode_FromASCII()
   to resize the output string

Found by Clang's static analyzer.

 * Formatting string, int, float and complex use the _PyUnicodeWriter API. It
   avoids a temporary buffer in most cases.
 * Add _PyUnicodeWriter_WriteStr() to restore the PyAccu optimization: just
   keep a reference to the string if the output is only composed of one string
 * Disable overallocation when formatting the last argument of str%args and
   str.format(args)
 * Overallocation allocates at least 100 characters: add min_length attribute
   to the _PyUnicodeWriter structure
 * Add new private functions: _PyUnicode_FastCopyCharacters(),
   _PyUnicode_FastFill() and _PyUnicode_FromASCII()

The speed up is around 20% in average.

 * Decode thousands separator and decimal point using PyUnicode_DecodeLocale()
   (from the locale encoding), instead of decoding them implicitly from latin1
 * Remove _PyUnicode_InsertThousandsGroupingLocale(), it was not used
 * Change _PyUnicode_InsertThousandsGrouping() API to return the maximum
   character if unicode is NULL
 * Replace MIN/MAX macros by Py_MIN/Py_MAX
 * stringlib/undef.h undefines STRINGLIB_IS_UNICODE
 * stringlib/localeutil.h only supports Unicode