Revert "picom: switch from compton to picom"

This reverts commit e6d1acc4ba. While
compton is unmaintained, it works for me. Unfortunately, I am unable
to find a solution to get picom working correctly. Both xr_gl_hybrid
and glx backends introduce some flickering while the xrender backend
is unable to remove tearing.

bin/xss-lock

@@ -40,9 +40,9 @@ case "$1" in
         xdotool key XF86AudioStop
         # Then, lock screen
         echo "lock: lock screen"
-        systemctl --user stop picom@${display}.service
+        systemctl --user stop compton@${display}.service
         i3lock -n -e -i $HOME/.cache/awesome/current-wallpaper-${display}.png -t -f
-        systemctl --user start picom@${display}.service
+        systemctl --user start compton@${display}.service
         echo "lock: unlock screen"
         ;;
 esac

requirements.txt

@@ -7,7 +7,7 @@ xss-lock
 libnotify-bin
 xfonts-terminus
 fonts-dejavu
-picom
+compton
 python3-xlib
 python3-pil
 fvwm

systemd/awesome@.service

@@ -2,7 +2,7 @@
 Description=Awesome window manager for %I
 PartOf=graphical-session@%i.target
 After=autorandr@%i.service
-After=picom@%i.service
+After=compton@%i.service
 After=xsettingsd@%i.service
 After=tmux.service
 After=ssh-agent.service

systemd/compton@.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Compositor for X11 on %I
+PartOf=graphical-session@%i.target
+
+[Service]
+Environment=DISPLAY=%I
+ExecStart=/usr/bin/compton --backend glx \
+                           --xrender-sync \
+                           --xrender-sync-fence \
+                           --vsync opengl-swc \
+                           --paint-on-overlay

systemd/graphical-session@.target

@@ -3,7 +3,7 @@ Description=Graphical user session for %I
 StopWhenUnneeded=yes
 Wants=autorandr@%i.service
 Wants=awesome@%i.service
-Wants=picom@%i.service
+Wants=compton@%i.service
 Wants=inputplug@%i.service
 Wants=misc-x@%i.service
 Wants=nm-applet@%i.service

systemd/picom@.service

@@ -1,7 +0,0 @@
-[Unit]
-Description=Compositor for X11 on %I
-PartOf=graphical-session@%i.target
-
-[Service]
-Environment=DISPLAY=%I
-ExecStart=/usr/bin/picom --vsync