We have temporary migration package xfce-extra/thunar-vfs, so in theory the: xfce? ( xfce-base/thunar ) depend could be changed to xfce? ( || ( xfce-extra/thunar-vfs xfce-base/thunar ) ) but I'd really prefer if you get rid of the support entirely, the library is obsolete and will be a blocker for us unmasking Xfce 4.7/4.8 It should be ported from ThunarVFS to GLIB's GIO.
To test this, unmask the xfce packages from profiles/package.mask, emerge new thunar and try to emerge avant-window-navigator, you'll find it fail at configure phase.
+ 16 Sep 2010; Samuli Suominen <ssuominen@gentoo.org> + avant-window-navigator-0.2.6-r1.ebuild, + avant-window-navigator-0.3.2.ebuild, + avant-window-navigator-0.3.2.1.ebuild: + Fix Xfce4 dependencies to accept xfce-extra/thunar-vfs as fallback for + Xfce 4.7/4.8 wrt #337549.