That is the code for wpa_supplicant which is the main GNU/Linux wireless network code to deal with secure wireless networks (I'm writing this right now through a wpa-supplicant connection). It apparently works under Windows too, but it is probably going to be harder to get it to compile. And if you have Linux, you can simply download the sources from repository (from the package manager).
But, in any case, the code is all in C, and comes with a Makefile. You should be able to simply issue the make command from a terminal (command-prompt) within the source folder (top-folder). Of course, this presupposes that you have "make" installed, and it comes with GCC (and many other compiler suites). Visual Studio C can also compile it (e.g., execute the makefile instructions). I suggest you read the README file and other compilation instruction from wpa-supplicant project itself.
If you can't get it to compile, it is probably a dependency issue. If you can find any more wpa-supplicant documentation on the dependencies required for compilation, make sure you follow them exactly. For the most part, you should be able to find packages through the software center for each dependency (make sure to download the -dev packages).