Google CP-SAT solver Rust bindings

Rust bindings to the Google CP-SAT constraint programming solver.

To use this library, you need a C++ compiler and an installation of google or-tools library files.

If you're using a recent version of or-tools, you'll also need libprotobuf (older versions used to link it statically). Invoke Cargo using RUSTFLAGS='-Clink-arg=-lprotobuf' cargo <command>.

The environment variable ORTOOLS_PREFIX is used to find include files and library files. If not setted, /opt/ortools will be added to the search path (classical search path will also be used).