The ebuild of sys-fs/squashfs-tools-4.1 has USE=xattr but ignores both settings: With USE=-xattr, the line XATTR_SUPPORT=1 should be removed from the Makefile. Conversely, with USE=xattr, the package should DEPEND on sys-apps/attr, since otherwise compilation will fail (I have not tried, but strongly assume that this is also a runtime dependency).
Created attachment 248599 [details, diff] Patch for the ebuild to fix the two mentioned issues
thanks, ive added that and fixed up the code in general http://sources.gentoo.org/sys-fs/squashfs-tools/squashfs-tools-4.1.ebuild?r1=1.1&r2=1.2