The current tcl-tk-8.33.ebuild is slightly broken. It does not install the private headers that are needed for tcl-tk apps to compile against. For example this is why tcl scripting is broken in the vim-6.0 ebuild. Also separate ebuilds for tcl and tk would be nice as it makes it easy to make ebuilds with tcl dependencies with out pulling in X at the same time. I am submitting ebuilds in that correct this bug.