gtkmm3 on msys2 gives "attempt to override closure->va_marshal"

[Damon Register <damonregister bellsouth net>]

After being stuck in the gtkmm2 world for a few years, I decided to
finally try moving up to gtkmm3.  After a bit of searching on-line,
it seemed that it was either Visual Studio or msys2 if I want to make
Windows programs.  I followed the procedure that I found for msys2
and was even able to build a few "hello world" programs.  The only
problem I have is that I see this message on closing any of the
programs:

GLib-GObject-WARNING **: attempt to override closure->va_marshal

After some searching on this and a trip upstairs for some Excedrin,
I could only find a few mentions but no answers though I think one
suggested it might be a bug in this version of gtkmm.  Is there anyone
who knows about this problem and can help?

I even tried a few tutorial examples such as the clock one, in case
my hello world code was missing something but they had the same
problem.

Damon Register