I am assuming your system does not contain something like tcl-devel, or in any case, the headers and configuration files for tcl. What distro do you use? People using that distro might be able to point out which package you really need (I am a slackie myself, so I usually have it all, or not at all).
Another thing you might want to try is using the --enable-tclk=no and/or --without-tclx switch for configure (you can also use --disable-tclk instead of the enable one).