ActiveTcl is ActiveState's quality-assured distribution of Tcl. 

# see <http://www.activestate.com/Products/ActiveTcl/>
#     <http://www.tcl.tk/>

If you want to use ActiveTcl binary package as the Tcl/Tk libraries, 
please use the following configure options.

   --with-tcl-dir=<ActiveTcl_root>
   --with-tk-dir=<ActiveTcl_root>

And use the followings if you need.

   --with-tcllib=<libname>
   --with-tklib=<libname>
   --enable-tcltk-stubs

For example, when you install ActiveTcl-8.4.x to '/usr/local/ActiveTcl', 

   configure --with-tcl-dir=/usr/local/ActiveTcl/  \
             --with-tk-dir=/usr/local/ActiveTcl/   \
             --with-tcllib=tcl8.4                  \
             --with-tklib=tk8.4                    \
             --enable-tcltk-stubs

It depends on your environment that you have to add the directory of 
ActiveTcl's dynamic link libraries to your library path when execute 
Ruby/Tk. 

# For example, on Linux, one of the ways is to use LD_LIBRARY_PATH 
# environment variable. 
# 
#   [bash]$ LD_LIBRARY_PATH=/usr/local/ActiveTcl/lib:$LD_LIBRARY_PATH \
#           ruby your-Ruby/Tk-script
#
#   [bash]$ LD_LIBRARY_PATH=/usr/local/ActiveTcl/lib:$LD_LIBRARY_PATH irb

Then, you'll be able to use Tcl/Tk extension libraries included in the
ActiveTcl package (e.g. call TkPackage.require('BWidget'), and then,
use functions/widgets of BWidget extention). 

                                  Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)