$ wget https://prdownloads.sourceforge.net/tcl/tk8.6.10-src.tar.gz
$ tar xvf tk8.6.10-src.tar.gz
$ cd tk8.6.10/unix/
$ mkdir build
$ cd build
$ ../configure --prefix=/opt/tk/8.6.10 --enable-threads --enable-shared --with-tcl=/opt/tcl/8.6.10/lib --x-includes=/opt/xorg/libX11/1.6.12/include --x-libraries=/opt/xorg/libX11/1.6.12/lib CFLAGS="-I/opt/xorg/xproto/7.0.31/include"
$ make
$ make install