Some builds require further packaging before they can be released:
make package-win32- Produces a signedSetup.exeinstall wizardmake package-osx- Produces aDMGfilemake package-linux- Produces a.debfile
The Windows package requires installing a valid certificate, see Code Signing a Windows Application and will also requiring installing the makensis and mono packages, installable from brew.
The Linux package is build using FPM which is a tool that makes it easy to build different package systems. FPM can be installed using gem install fpm, you will likely need to install a better ruby and gnu-tar than what ships with OS X. brew install ruby gnu-tar