gtk2 apps aborting with assertion "character != 0" failed: file "xdgmimecache.c", line 462, function "cache_glob_node_lookup_suffix"

[David Brownlee <abs%absd.org@localhost>]

        With the latest pkgrsc (from last night), gtk2 using apps abort
        with the following error when I try to change directories in
        the file save dialog:

assertion "character != 0" failed: file "xdgmimecache.c", line 462, 
function "cache_glob_node_lookup_suffix"

        Tested in at least evince, gimp, and firefox3.

        Has anyone else seen this? This is on i386 5.0_RC4 and first
        noticed when I updated pkgsrc a few days ago, but rebuilding
        from the latest pkgsrc still shows the same behaviour.

        This system was installed from binary packages (/usr/pkg and
        /var/db/pkg* nuked and then packages installed). Interestingly
        when I 'ssh -Y' to the system which built the packages and
        run evince there back to this system's display it doesn't
        exhibit the issue...