grass-6.0.1 has tcltk as a use flag, but it always uses the wish command, which is missing if you don't have tcltk Reproducible: Always Steps to Reproduce: 1. 2. 3.
I'm not sure I understand this; yes Grass has USE flag for tcltk, which installs both the tcl and tk packages. This is required for some of the Grass GUI features, however, I believe X is the only hard requirement. There are reasons to build without tcltk support (eg, libgrass support for gdal), so what exactly is the problem?
I emerged grass-6.0.1 without the USE flag for tcltk set and the grass startup script (grass60) complained about the missing "wish" command, which seems to be part of tcltk, so it think this should be hard requirement.
By "complaining", do you mean that installation failed, or was it just a warning? If installation failed, please post the resulting error message.
it installs fine, but if you try to run the grass60 start-script at some point it fails and tells you that the wish command is missing. so grass60 is unusable without tcl/tk enabled. to reproduce rename the wish command to some other name and try running grass60.
It looks like Grass 6.x now indeed requires the wish tcl shell; it's no longer a USE flag in newer Grass (6.0.1 to be precise).