As for other packages, xorg-x11 should not depend on util-linux unconditionally as this breaks non-GNU/non-Linux userlands. The attached patch fixes the problem (all xorg-x11 versions are affected). Modular X doesn't seems to be affected (still doesn't compile on G/FBSD, tho).
Created attachment 65867 [details, diff] Ebuild patch
Which bsd package provides `col`?
This is fixed now.