PaX marking during build for mono & others

Hi, currently several ebuilds sed some build scripts inject a paxctl
call to mark the executable in various ways. However paxctl does not
handle xattr marking, leading e.g. to bug #467238 [1].
pax-utils.eclass correctly handles this cases checking the PAX_MARKINGS
variable.
The pax-mark function should become a standalone script to include in
elfix, portage or maybe just generate a script (e.g. pax-mark.sh) and
copy it in the build directory and inject pax-mark.sh instead of paxctl.

Grepping /usr/portage these are packages which most probably are
affected by the same problems:

sys-boot/grub-0.96-r1
net-libs/webkit-gtk-* (gir-paxctl-lt-wrapper script)
www-client/epiphany-*
www-client/luakit-9999
dev-lisp/sbcl-*
app-emulation/wine-*
app-emulation/qemu-user-0.9.0 (?)
dev-lang/mono-*

What's the most appropriate way to go?

Thanks,
-- 
Ale

[1] https://bugs.gentoo.org/show_bug.cgi?id=467238