The flc() input file consists of two sections, separated by a line containing
`tt(%%)'. The section above tt(%%) contains option specifications and
definitions; the section below tt(%%) contains the regular expressions (and
their (optional) actions). The general layout of flc()'s input file,
therefore, looks like this:

    verb(
definitions
%%
rules
    )

Optionally, a final line containing `tt(%%)' may follow the rules.  The
following sections cover the `definitions' and `rules' sections.

