Description:

Optcomp is a camlp4 syntax extension which handles #if, #else, etc
directives in ocaml source files.

The difference between cpp and optcomp is that optcomp is more
caml-friendly than cpp:

* it does not interpret "//", "/*", and "*/" as comment delimiters
* it does not complains about missing "'"
* it is easier to integrate in the build process when using other
camlp4 syntax extensions

By the way optcomp does not do macro expansion while cpp does.

The difference between pa_macro and optcomp is that optcomp does not
require code that will be dropped to be valid caml code. So for
example some code that will be rejected by camlp4+pa_macro will be
accepted by camlp4+optcomp.

You can use optcomp with ocamlfind, with the package optcomp or you
can directly include it in your project.