* Makefile.in (nettle_SOURCES): Added sha384-meta.c.

* sha384-meta.c: New file.

* sha.h: Added declarations for sha384. Some are aliases for the
corresponding sha512 definition.

* sha512.c (sha512_write_digest): New function.
(sha512_digest): Use it.
(sha384_init): New function.
(sha384_digest): New function.

Rev: nettle/ChangeLog:1.59
Rev: nettle/Makefile.in:1.19
Rev: nettle/nettle-meta.h:1.4
Rev: nettle/sha.h:1.5
Rev: nettle/sha384-meta.c:1.1
Rev: nettle/sha512.c:1.4