At the moment sux has a DEPEND="virtual/x11", however it does not actually require virtual/x11 to build (since there is no compilation) and it is questionable whether the whole of x11 is required as an RDEPEND since this is just a shell script that messes with environment variables. It also has the /usr/X11R6/bin/xauth path hardcoded inside it. Both of these will break sux under modular X.
Created attachment 75027 [details, diff] sux-1.0-r2 modular X dependencies
Created attachment 75029 [details, diff] Patch for sux utility so as not to use X11R6
Fixed in -r3.