A long while back the people who develop the HexChat IRC Client (a fork of XChat) contacted me to let me know that they were dropping my Tcl language plugin entirely due to their inability to get it working under Windows. I don't use Windows so I couldn't be of much help. I have no recollection as to what the issue was but by looking at their commentary on the subject, they didn't seem too interested in trying and it looks like they gave up part way through because it would no longer compile under Linux either.
Since I recently moved over to HexChat (on Linux, not Windows) I took a few seconds to fix the code so it once again compiles on Linux and I have made it available at here. Contrary to rumor, the plugin is not dead, it's just feature complete until someone comes up with ideas for new features.
As long as you have TCL installed, it should compile with:
cc tclplugin.c -O2 -Wall -fPIC -shared -ltcl -o tcl.so
When done, move it to your HexChat /addons directory.
The docs for the plugin itself can be found here.