Immediately after startup, Premake will look for and run a system script. It does this before handling actions and other arguments, and before loading the project script, if present. The system script is a great place for adding modules and other support code that you wish to include in all of your Premake-enabled projects.
By default, this file is named
premake5-system.lua, and should be located somewhere on Premake's search paths.
You can override the default system script file name and location using the
--systemscript command line argument.
$ premake5 /systemscript=../scripts/my_system_script.lua vs2010
There is nothing particularly special about this file other than its run-first priority. You can put any Premake code in the system script, including configurations, workspaces, and projects.