I have packaged and uploaded zeek  and zeek-broker  into the Arch user repository.
I’ve tested the install on a few different systems and it seems to work. I plan on maintaining these packages long term because zeek is awesome.
The flags I’ve configured for zeek-broker are minimal because the only current user (me) requires the headers and the shared objects. So, let me know either here or in the comments in the aur if flag x,y,z would be nice to have by default and I’ll turn them on.