1 - Basics
libgit2 (https://libgit2.org) is a portable, pure C implementation of the Git core methods.
libgit2 is distributed in source form only. Distributions can be obtained from the download page at https://github.com/libgit2/libgit2/releases. Build instructions can be found at https://libgit2.github.com/docs/guides/build-and-link/.
The build system is based on CMake CMake, a cross-platform, open-source build system. If you are not familiar with CMake don't worry: to build libgit2 you don't need to know much. Just install CMake and follow the build instructions. However if you want to know more about CMake we provide a CMake tutorial.