lang/python310: add LibreSSL support

LibreSSL 3.6 and later are fully compatible with PEP-644 for the
ssl and hmac modules, but not hashlib due to missing SHA-3/SHAKE,
BLAKE2 and scrypt. Partially reverts
https://github.com/python/cpython/commit/39258d3595300bc7b952854c915f63ae2d4b9c3e
for _hashopenssl.c only to allow LibreSSL to work.

(Python 3.11 and later need a different implementation due to
configure-time checking)