[hypermail] compiler warning: `vfscanf' redefined

ear Guru,

When I compile hypermail I get lots of warnings about vfscanf being redefined in trio.h.

As far as I can understand, at first the hypermail authors wanted to use system vfscanf if it is available and fall back to trio_vfscanf if not.
But later it was decised to use trio_vfscanf always. Thus system libs are not tested for vfscanf by configure and thus HAVE_VFSCANF never gets defined.
What are the reasons for this decision?

Or it is just a tiny bug, easily fixed by a change in configure.in?

                        Sincerely, Michail