Compile emacs-lucid --with-modules on WSL Debian (buster)

debian-build-emacs-lucid-with-modules.sh

# install Debian emacs-lucid (will be replaced later)
sudo apt install emacs-lucid

# install all build dependencies
sudo apt-get build-dep emacs-lucid
sudo apt install build-essential devscripts ed

# make a temporary directory and dowload debian source (+ patches)
mkdir TEMPDIR
cd TEMPDIR
apt-get source emacs-lucid
cd emacs-26.1+1

# modify debian/rules file to add "--with-modules" configuration parameter
ed debian/rules <<EOF
s/mailutils/mailutils --with-modules/
w
q
EOF

# build emacs
# - will take some time
# - the first attempt fails but creates emacs-module.h, the second attempt succeedes
# - since WSL has problems with fakeroot daemon, use sudo (-rsudo) instead 
debuild -b -uc -us -rsudo
cp debian/build-lucid/src/emacs-module.h src/
debuild -b -uc -us -rsudo

# replace emacs-lucid with self-built version
cd ..
sudo dpkg -i emacs-lucid_26.1+1-3.2+deb10u1_amd64.deb

# cleanup (be careful, better save emacs-lucid_26.1+1-3.2+deb10u1_amd64.deb first)
cd ..
rm -rf TEMPDIR

# run emacs
# - alternatively create a start menu shortcut with: C:\Windows\System32\wsl.exe env DISPLAY=:0 emacsclient -n -c -a ""
emacsclient -n -c -a ""

# notes
# - emacs-lucid behaves better than emacs-gtk when run in server-mode and X11 crashes (happens on Windows)
# - as X11-server try MobaXTerm in "Multiwindow mode" with DPI set to "auto" in X11 preferences