I am setting up a Windows-based build server for my Unity builds. Everything is working 100% on the windows side, but I haven’t figured out how to set up the OSX Build Target install via commandline. Here is the method I used to install Unity “silently”:
Is there a switch to add the Mac OSX Build Target?
It turns out that it needs to be installed manually after the fact, in our case since the process is scripted, we needed to grab the file directly from Unity instead of using the installer:
http://netstorage.unity3d.com/unity/a9f86dcd79df/TargetSupportInstaller/UnitySetup-Mac-Support-for-Editor-2017.3.0f3.exe