Unless you have lots of different diffprogs to use in different places … maybe consider setting that environment variable somewheres. Big global would be /etc/environment, ex:
EDITOR=/usr/bin/micro
SUDO_EDITOR=/usr/bin/micro
VISUAL=/usr/bin/kate
DIFFPROG=/usr/bin/meld
XCURSOR_SIZE=36
QT_AUTO_SCREEN_SCALE_FACTOR=1
WINEDLLOVERRIDES="explorer.exe=d"
Aaaand … I also whipped up a patched pacdiff that adds a polkit-powered ‘edit’ option to pacdiff … its here for those that want to try it…
https://0x0.st/HNgz.sh
(just save the script and run normally (ex: pacdiff-patched.sh)… a new e option will be possible)