otherwise we get a nice 'no previous prototype' due to -Wmissing-prototypes.

thinks rsa and ecdsa may be used un-initialized... if we enter the branch with fatalx(). sigh

otherwise we fail the openssl test 'libcrypto libssl'

some CI envs don't like `listen on localhost' but tolerate INADDR_ANY or IN6ADDR_ANY_INIT.

Listening by default on all the addresses is so bad I don't know why I haven't changed this before. Anyway. Add a `listen on $hostname port $port' syntax to the config file and deprecate the old "port" and "ipv6" global setting. Still try to honour them when no "listen on" directive is used for backward compatibily, but this will go away in the next next version hopefully. At the moment the `listen on' in server context don't filter the host, i.e. one can still reach a host from a address not specified in the corresponding `liste on', this will be added later.

unlike the name might suggest, proc_kill() doesn't use kill(2) so proc is not needed.