When b() is called without any arguments it generates the following usage
information: 
    COMMENT(The usage file should be removed by cleanup, in order to make sure
            that it is created using the latest bisonc++ version)

    TYPEOUT(
    If a message about a failing NOEXPANDINCLUDE is shown, create the file 
`usage' in documentation/manual/invoking containing the latest usage info
)
    verbinclude(usage.txt)

