Cpp tcl86

In tcl8.5 a number of macros were defined as returning char* and have been changed to return void*.  I added the cast to char* explicitly where it was not to avoid type conversion errors.  I also changed the README.FreeBSD configure line to use --with-tcl=/usr/local/lib/tcl8.6 instead of --with-tcl=/usr/local/lib/tcl8.5