Solution: regenerate

Solution: add zstr_send[m]_compress and zstr_recv_compress to the API
and add dependency to lz4

Solution: do it

Solution: regenerate

Solution: assert if zmq_msg_init_size returns an error, which can
happen when size > 33 bytes due to a malloc failure (OOM).
Otherwise the following memcopy will write on random memory.

Solution: install libsystemd-dev and liblz4-dev.
Install lz4 on OSX only for the legacy builds as an optimisation.
Running brew update takes many minutes and slows down the build
considerably, so only do it where it's already been done as the
legacy builds require libsodium.