Merge branch 'wip/dueno/cipher-deinit' into 'master'

tests: hash-large: exercise gnutls_hash_output(..., NULL)

Closes #1453, #1552, #1559, #1560, and #1565

See merge request gnutls/gnutls!1851

diff --cc configure.ac
Simple merge

diff --cc lib/nettle/pk.c
Simple merge