DJGPP is a set of tools for the use of the GNU tools (and therefore legOS) within DOS.
You can find instructions on how to get and install DJGPP and legOS from Rossz Vamos-Wentworth's page. There may or may not be more up-to-date instructions in the legOS HOWTO.
The file listing below is auto-generated, showing the current list of files in this directory. To get more information about them, try the links above or download them yourself.