long story short, mount your portage dir via NFS from somewhere, install an ebuild that does something like `dosbin ${FILESDIR}/...` (or similar) in `src_install()`, and you'll see that it will fail with a message like this: install-xattr: setxattr() failed: Operation not supported This message (while misleading) is, because your portage directory is mounted via NFS and thus, your $FILESDIR is being listxattr(2)'d returning values that install-xattr binary cannot getxattr(2). Whilst this looks like a bad behaviour of the NFS mount, one may want to imply, that install-xattr (used by portage by *default*) should be able to handle those cases. Best Regards, Christian Parpart.
Please export PORTAGE_INSTALL_XATTR_IMPLEMENTATION="python" to try it with portage's internal install-xattr implementation, and see if that outputs any more useful information. The fact that it complains about setxattr failing suggests that you lack xattr support inside ${PORTAGE_TMPDIR}.
