As far as I can tell, that virtual/x11 dependency can be dropped. No script I
have shows a dependency on any X libs.
I briefly looked at the provided configure.in and didn't see any X references
there either.
dev-lang/erlang/erlang-10.2.7.ebuild includes a RDEPEND "X? ( virtual/x11 )"
and a DEPEND "X? ( dev-lang/tk )".
If the dependency is on Tcl/Tk rather than directly on X11 then I suggest
removing the dependency on virtual/x11 and instead using the tclck USE flag and
depending only on dev-lang/tk, i.e.
tcltk? ( dev-lang/tk )
If there is a real dependency on X11 then you need to replace X? ( virtual/x11
) with the correct modular X dependencies.
Cheers,
Tom