The cargo target directory tree is now populated with a cmake package
file and that's also installed into the prefix specified with the cargo
cmake xtask.
As a consequence, the cpptest example can be built by first building the
cmake package:
cargo xtask cmake
or
cargo xtask cmake --release --target some-triplet)
or
cargo xtask cmake --release --prefix /somewhere --install
and then run cmake in the cpptest example with a prefix path:
-DCMAKE_PREFIX_PATH=/where/you/installed/it or simply
-DCMAKE_PREFIX_PATH=../../target/debug for example.
Pending still is the sixtyfps compiler tool installation and discovery.
