This is probably the most complex part of the new buildsystem. This
adds the following targets:
- Linux:
make install - installs to $(prefix) (default: /usr)
The install path can be changed during make install time.
- Windows:
make install - installs Subsurface and its dependencies to
packaging/windows.
- Mac:
make mac-deploy - populates Subsurface.app with the dependencies
make install - mac-deploy + install Subsurface.app to /Application
make mac-create-dmg - mac-deploy + creates Subsurface-$VERSION.dmg
Signed-off-by: Thiago Macieira <thiago@macieira.org>
