Silence Python 3.8 PY_SSIZE_T_CLEAN warning
In Python 3,
PyArg_ParseTuple and friends can return either an int
or a Py_ssize_t type for the length in an argument of the form
"u#", etc, controlled by whether the preprocessor
PY_SSIZE_T_CLEAN is defined when the header
included. A future version of Python will only support
In Python 3.8, there was a deprecation warning added (see
PY_SSIZE_T_CLEAN macro to suppress the hundreds or
thousands of deprecation warnings that may be printed when reading
a LIGO_LW file.
See also lscsoft/glue!69.