You'll need the following dependencies:
- cmake
- libaccounts-glib-dev
- libcanberra-dev
- libgcr-3-dev
- libgirepository1.0-dev
- libglib2.0-dev
- libgmime-2.6-dev
- libgranite-dev
- libgsignon-glib-dev
- libgtk-3-dev
- libsecret-1-dev
- libsqlite3-dev
- libunity-dev
- libwebkitgtk-3.0-dev
- libxml2-dev
- valac (>= 0.26)
It's recommended to create a clean build environment
mkdir build
cd build/
Run cmake to configure the build environment and then make to build
cmake -DCMAKE_INSTALL_PREFIX=/usr ..
make
To install, use make install, then execute with pantheon-mail
sudo make install
pantheon-mail