cfengine-cf-promises is a variable defined in `cfengine.el'.
Its value is

The location of the cf-promises executable.
Used for syntax discovery and checking. Set to nil to disable
the `compile-command' override. In that case, the ElDoc support
will use a fallback syntax definition.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.4 of Emacs.