Compile warnings with DEC cxx

[Angus Leeming]

Compiling current CVS I'm getting lots of warnings like:
cxx: Warning: insets/insetquotes.h, line 83:
          "LyXFont InsetQuotes::ConvertFont(const LyXFont &)" does not match
          "Inset::ConvertFont" -- virtual function override intended?
        LyXFont ConvertFont(LyXFont const & font);

In lyxinset.h:
        virtual LyXFont ConvertFont(LyXFont font);
in insetquotes.h:
        LyXFont ConvertFont(LyXFont const & font);

Which should it be?
Angus