$mid = $1;
} else { # Message-ID header not found, synthesize a message id
# based on SHA1, as notmuch would do. See:
- # http://git.notmuchmail.org/git/notmuch/blob/HEAD:/lib/sha1.c
+ # https://git.notmuchmail.org/git/notmuch/blob/HEAD:/lib/sha1.c
my $sha = Digest::SHA->new(1);
$sha->add($_) foreach(@headers);
$sha->addfile(\*STDIN);