Now a (void *) but previously an integer.
These macros resolve the codebase allowing it to be built against both
tcl8 (8.5, 8.6) and tcl9 (9.0).
tar -zxvf tcl9.0.0-src.tar.gz
cd tcl9.0.0/unix
./configure --enable-symbols --prefix=/opt/tktcl9
make install
tar -zxvf tk9.0.0-src.tar.gz
cd tk9.0.0/unix
./configure --enable-symbols --prefix=/opt/tktcl9 --with-tcl=/opt/tktcl9/lib
make install
cd magic
./configure --with-tk=/opt/tktcl9/lib --with-tcl=/opt/tktcl9/lib