I maintain the myth* ports for Mac OS X at MacPorts. Currently, that is mythtv-core.28, mythweb.28, mythtv-core.27, mythweb.27. Older ports, mythtv-core.25, mythweb.25, mythtv-core.26 and myth web.26, have been marked obsolete and will be deleted from the ports tree in late 2018.
I also prepare standalone all-in-one installers for OS X. These are standard Mac OS X installer packages that contain everything needed to run Myth fronted, backend, MythWeb and the database server on your Apple Macintosh.