The ebuild for fluxbox-0.17-r3 is corrupt in some way and causes a syntax error while doing a dependency scan for a world update. It fails to find a close " on line 58.
use gnome && myconf="${myconf --enable-gnome" \ || myconf="${myconf} --disable-gnome" should be: use gnome && myconf="${myconf} --enable-gnome" \ || myconf="${myconf} --disable-gnome"
Sorry, this was my fault. In cleaning up, I neglected to close the { around a myconf.