The Easy-C compiler is available as a single download file called easy_c.zip. You download the file (< 1MB), unpack it, and read the file called README.txt. The easy_c.zip file contains 1) a Linux executable, 2) all source files, and 3) a bootstrap script. That is all there is to it.
I suspect that it would be possible to bootstap the compiler onto MacOS. Windows would be a bit more problematic, but it would probably work using CyWin. I have not bothered to investigate either the MacOS or Windows option very carefully due to an extreme lack of interest on my part.