PMS disallows lookups of ${IUSE} from eclasses (it is undefined what exactly is in there at that point). gnome2 uses that for gtk-doc magic and .la punting; both should be replaced by more explicit solutions.
Ok, we decided to keep using IUSE like this, so please just migrate your has ${IUSE//magic} to in_iuse() from eutils.eclass.
http://git.overlays.gentoo.org/gitweb/?p=proj/gnome.git;a=commitdiff;h=f3c55f4fd61a2abccd1d7c528d76804e45da88a9 In the second hunk the following code can be used: if ! use_if_iuse static-libs; then
updated in overlay.
Commited to the tree a few days ago.