It has been noted here that Tcl/Tk, and in turn gitk now require X11 under Cygwin.

Having run it before and after this change it seems like extreme overkill. I use gitk very lightly, mostly sticking to simply command line git.

How could I go about using gitk without X11, perhaps manually installing old version of Tcl/Tk?

After some tinkering, I came up with this script that allows gitk without X11

#!/bin/sh
# Requires Cygwin packages: git, make, mingw64-i686-gcc-core, wget 

# Install Tcl
wget prdownloads.sf.net/tcl/tcl8.5.12-src.tar.gz
tar xf tcl8.5.12-src.tar.gz
cd tcl8.5.12/win
./configure --host i686-w64-mingw32
make install
cd -

# Install Tk
wget prdownloads.sf.net/tcl/tk8.5.12-src.tar.gz
tar xf tk8.5.12-src.tar.gz
cd tk8.5.12/win
./configure --host i686-w64-mingw32
make install
cd -

# Install gitk
cd /usr/local/bin
wget raw.github.com/git/git/master/gitk-git/gitk
chmod 700 gitk
echo 'cygpath -m "$1" | xargs -I% wish85 % -- ${@:3}' > wish
cd -