Install pygit2 0.22.0 on a minimal Ubuntu Trusty

gistfile1.sh

apt-get install -y pkg-config python-pip git libssl-dev zlib1g-dev cmake python-dev libffi-dev libssh2-1-dev

git clone https://github.com/libgit2/libgit2 \
  && cd libgit2 \
  && git checkout tags/v0.22.0 \
  && mkdir build \
  && cd build \
  && cmake .. -DCMAKE_INSTALL_PREFIX=/usr \
  && cmake --build . --target install \
  && cd ../..

git clone https://github.com/libgit2/pygit2 \
  && cd pygit2 \
  && git checkout tags/v0.22.0 \
  && python setup.py install \
  && cd ..