auto-upgrading strings to utf8

[Quentin <squentin free fr>]

With gtk2-perl, most strings passed as arguments to a glib/gtk function
are auto upgraded to utf8,
that's not the case in C, where arguments must be in the proper encoding
before passing it as an argument to a gtk/glib function.
Which leads to a problem with the Gstreamer bindings where the filenames
is a string property of a Glib object, and thus are auto upgraded to
utf8, but they shouldn't.

So, following a chat with muppet on IRC, we were wondering if
automatically upgrading text to utf8 is the right thing to do?

I tried disabling auto-upgrading in Glib, and my program (a very complex
jukebox) runs fine because all the data I use are utf8, so there is no
need to upgrade strings to utf8 in this case.

The problem is how to keep existing code working...

Any thoughts on how to fix the problem ?