The configure scripts of all versions of tcldom in portage cannot find tclConfig.sh because of my multilib layout and (my) refusal to link /usr/lib to /usr/lib64. Also, the ebuild for tcldom is a little dirty ;-).
Created attachment 207879 [details] /tmp/tcldom-multilib-eapi2-compile.patch multilib compilation, cleanup
Created attachment 207880 [details] /tmp/tcldom-3.1_build.log example ./configure error
Included thanks.