Users running Mountain Lion and the latest version of XCode (4.6.3) will also need to install libtool, automake and autoconf.
They are easy enough to install, grab them from http://www.gnu.org/software/libtool/, http://www.gnu.org/software/autoconf/ and http://www.gnu.org/software/automake/, then follow these steps for each:
You have to [modify your PATH environment variable](http://www.computerhope.com/issues/ch000549.htm) so that it contains MinGW's bin folder path. With default settings, the bin folder is located at `C:\MinGW\bin`, which means that you would have to append `;C:\MinGW\bin` to the PATH variable.
Then you should either clone this repo by using git, or just download a [zip of current Master branch](https://github.com/irungentoo/ProjectTox-Core/archive/master.zip) and extract it somewhere.
After that you should get precompiled packages of libsodium from [here](https://download.libsodium.org/libsodium/releases/) and extract the archive into this repo's root. That is, `sodium` folder should be along with `core`, `testing` and other folders.