tar xzvf gcl-2.2.2.tar.gz
cd gcl-2.2.2
[ this adds the /usr/info path, and selects dynamic compilation ]
zcat gcl-2.2.2.diff.gz | patch 
[ if the tclConfig.sh and tkConfig.sh are in /usr/lib on slackware add
 a third argument to ./add-defs to give that directory... ]
% ./add-defs 386-linux /usr/lib
% make
% make install "PREFIX_DIR=/usr"