sha1dc: use buffer protocol when parsing arguments Without this, functions won't accept bytearray, memoryview, or other types that can be exposed as bytes to the C API. The most resilient way to obtain a bytes-like object from the C API is using the Py_buffer interface. This commit converts use of s#/y# to s*/y* and uses Py_buffer for accessing the underlying bytes array. I checked how hashlib is implemented in CPython and the the implementation agrees with its use of the Py_buffer interface as well as using BufferError in cases of bad buffer types. Sadly, there's no good way to test for ndim > 1 without writing our own C-backed Python type. Differential Revision: https://phab.mercurial-scm.org/D7879