The GDOC script is taken from:

   http://git.savannah.gnu.org/cgit/libidn.git/plain/doc/gdoc

and then modified %highlights_texinfo to use @var for parameters.

The file 'chopstx-api.texi' is generated by: 

  $ ./gdoc -texinfo ../chopstx.c >chopstx-api.texi

Then, we generate chopstx.info by:

  $ makeinfo -o chopstx.info chopstx.texi