Powerline font in framebuffer console

When using a "Powerline"-based prompt such as ZSH agnoster, the prompt looks good in a graphical terminal emulator, but will probably look garbage in the framebuffer or VGA console, due to the missing font glyphs.

There is a special bitmap-based powerline font suitable for the framebuffer console. On some systems the console setup tool setupcon is buggy and has to be patched in order to enable loading a custom font.

Download bitmap font from powerline repository
Copy the ter-powerline-*.psf.gz files to /usr/share/consolefonts
Add FONT=... to /etc/default/console-setup. It may be worth to experiment with different font sizes depending on screen resolution.
```
FONT="ter-powerline-v32n.psf.gz"
```

/bin/setupcon has a bug preventing it from finding and activating the font. Fix with following patch:

--- /bin/setupcon.orig 2020-07-29 08:57:20.792643590 +0200
+++ /bin/setupcon 2020-07-29 09:11:24.295472896 +0200
@@ -684,10 +684,11 @@
             fdec="${f%.gz}"
             RES=`findfile $fontdir $fdec`
         fi
-        FONTFILES="$FONTFILES $RES"
+        FONTFILES="$RES"
     done
 fi
 FONTFILES=`echo $FONTFILES` # remove extra spaces
+
 if [ -n "$FONTFACE" -a -z "$FONTFILES" ]; then
     case "$kernel" in
         linux)

Run setupcon

Now the Terminus powerline font should be active in the framebuffer console.