Ok. I think I've figured out what's going on here.
The current xmms-musepack plugin code links in both glib-1.2 and glib-2.0. According to this bug in the redhat bug database:
https://bugzilla.redhat.com/bugzilla/show_b...g.cgi?id=131609
this is a no-no. I'm not sure why it only manifests itself on amd64 machines.
As a workaround I've just commented out the calls to the glib-2.0 utf8 string conversions functions, which seem to be the only reason the code needs glib-2.0. As an added bonus, I've ported the xmms plugin code to the new C libmusepack.
This work in progress is available on my svn server (
http://www.caddr.com/svn and
http://www.caddr.com/websvn).
It seems like a better solution would be to change the code to use libiconv for character conversion, right? At least I can listen to my mpc files on my amd64 machine now.