Define extern `PyBUF_MAX_NDIM` (GH-3811)
Define extern `PyBUF_MAX_NDIM` (GH-3811)

Ensure that Cython exposes `PyBUF_MAX_NDIM` from Python as part of
`cpython.buffer` to allow access to developers.
cython/cython,cython/cython,scoder/cython,da-woods/cython,cython/cython,scoder/cython,scoder/cython,cython/cython,da-woods/cython,scoder/cython,da-woods/cython,da-woods/cython