DOCBOOK: RFE 473365: Allow optional in funcprototype

[Norman Walsh <ndw@nwalsh.com>]

See https://sourceforge.net/tracker/index.php?func=detail&aid=473365&group_id=21935&atid=384107

This RFE requests optional parameters in a function synopsis. Traditional UNIX
man pages address this problem by repeating the signature:

int foo(int bar);
int foo(int bar, char *baz);
etc.

But overloaded functions have become fairly common so it seems likely
that others have been faced with this issue.

How did you deal with it? What markup would you like to see?

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com>      | Reality is what refuses to go away
http://www.oasis-open.org/docbook/ | when I stop believing in
Chair, DocBook Technical Committee | it.--Philip K. Dick