what are you intending to use libressl for in native plan9?
plan9 already has a crypto library (libsec) which is a fraction of the
size of openssl and works quite well. i'v been using it to implement
many crypto protocols to talk to the outside world.

for tls, plan9 uses devtls which allows you to wrap any file descriptor
to make it a encrypted channel and then you get a filedescriptor back
that you can pass arround, so the programs communicating actually dont
even need to know the secret session keys. so adding tls support to
programs is very trivial in plan9. one function call basically to wrap
the fd. while in unix programs that want encryption have to change all
ther read and wirte calls to use special libssl functions.

also, plan9 has factotum to hold and work on secret keys. you can use
factotum todo the public key operations like signing, encryption and
decryption using the key for you so keys never have to leave factotum.

even if you port programs from unix, it might be worth taking a step
back and learn how plan9 does crypto, which is quite advanced compared
to traditional unix.

--
cinap