[ANN] cppo 1.6.0: jbuilder build

cppo is a crude preprocessor similar to the C preprocessor, but better suited to deal with OCaml-like syntaxes. It supports familiar directives such as #include, #define, and #if.

This release now builds and installs cppo using jbuilder rather than the ever-broken makefile that we used to have. Big kudos to Rudi Grinberg, who did all that work.

There are no new features and everything should work as before. If not, please let us know.