• Convert unicodeobject.h macros to static inline functions.

• Reorder functions to declare functions before their first usage.

• Add "kind" variable to PyUnicode_READ_CHAR() and
  PyUnicode_MAX_CHAR_VALUE() functions to only call PyUnicode_KIND()
  once.

• PyUnicode_KIND() now returns an "enum PyUnicode_Kind".

• Simplify PyUnicode_GET_SIZE().

• Add assertions to PyUnicode_WRITE() on the max value.

• Add cast macros:

  • _PyASCIIObject_CAST()
  • _PyCompactUnicodeObject_CAST()
  • _PyUnicodeObject_CAST()

• The following functions are now declared as deprecated using
  Py_DEPRECATED(3.3):

  • PyUnicode_GET_SIZE()
  • PyUnicode_GET_DATA_SIZE()
  • PyUnicode_AS_UNICODE()
  • PyUnicode_AS_DATA()
  • The implementation of these functions disable deprecation
    warnings in their body.

• PyUnicode_READ_CHAR() now uses PyUnicode_1BYTE_DATA(),
  PyUnicode_2BYTE_DATA() and PyUnicode_4BYTE_DATA().

• Replace "const PyObject*" with "PyObject*" in _decimal.c
  and pystrhex.c: PyUnicode_READY() can modify the object.

• Replace "const void *data" with "void *data" in some unicodedata.c
  and unicodeobject.c functions which use PyUnicode_WRITE(): data is
  used to modify the string.

https://bugs.python.org/issue45490