cperciva's libmd implementation is 5-30% faster
The same was done for SHA256 previously in r263218
cperciva's implementation was lacking SHA-384 which I implemented, validated against OpenSSL and the NIST documentation
Extend sbin/md5 to create sha384(1)
Chase dependancies on sys/crypto/sha2/sha2.{c,h} and replace them with sha512{c.c,.h}
Reviewed by: cperciva, des, delphij
Approved by: secteam, bapt (mentor)
MFC after: 2 weeks
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D3929
Add a prefix to all symbols in libmd to avoid incompatibilites
with same-named, but not binary compatible, symbols from libcrypto.
Also introduce Weak aliases to avoid the need to rebuild dependent
binaries and a major version bump.
PR: 199119
Differential Revision: D2216
Reviewed by: roberto, delphij
MFC after: 2 weeks
