Whenever we run a program compiled with GTK+ on MSYS2 and MinGW/GCC - and possibly other build environments, I dunno - a message of the following form is given at exit:

> (a.exe:4744): GLib-GObject-WARNING **: attempt to override closure->va_marshal (0000000063a48a20) with new marshal (0000000066710f98)


I am far from the only person who has noticed and been worried by this; here are just a few other examples:

 * https://mail.gnome.org/archives/vala-list/2016-June/msg00064.html
 * https://mail.gnome.org/archives/gtkmm-list/2016-August/msg00023.html
 * http://forum.gtkd.org/groups/GtkD/thread/459/


We can see that the error is coded in gobject/gclosure.c:
> https://git.gnome.org/browse/glib/tree/gobject/gclosure.c#n899


Mercifully, there don't appear to be any other problems (other than resources needing copied into the output exe's folder, etc.). But is this something that needs fixed?


I must stress this is literally the only 'problem' I have with GTK+/gtkmm stuff in MSYS2 - given how easy MSYS2 makes it and how GDK Win32 just works effortlessly. My programs look and function exactly on Win32 as in my main development on GNOME (and AFAIK my even lesser tested OS X) - so I'm hugely grateful to everyone who's made cross-platform development as trivial as this!


HTH and thanks in advance.