warning message control: parameter patch

[DJ Delorie]

> One fell swoop is fine, so long as the right ChangeLog entries end up in 
> the right place.

Done (whew).

The next two steps are:

1. Assign non-zero values to all those zeros.  I think the best thing
   to do is use the OPT_* constants from options.h since that pulls in
   all the logic we need to coordinate the namespaces and such between
   languages.

2. Write the code to do something with those non-zero values.

Note that these can be done in any order, or in parallel, and if
anyone wants to start replacing those zeros with OPT_* values in the
parts of the source they maintain, go right ahead!  ;-)