Luckily, after a brief look in /etc/fonts, I found that font configuration now follows the nice pattern of a conf.avail directory containing all the available configuration parts, and conf.d containing symlinks to these parts.  This makes enabling bitmap fonts even simpler now:

# "Un-disable" bitmap fonts
sudo rm /etc/fonts/conf.d/70-no-bitmaps.conf
# Clear the font cache
sudo fc-cache -f -v

Now you should be able to drop bitmap (i.e. PCF) fonts into ~/.fonts as you would with TTF fonts and be able to use them with no extra hassle.

Update: Andreas asked in the comments if there was a way to do this that doesn’t require root access. In fact there is! If you copy /etc/fonts/conf.avail/70-force-bitmaps.conf to ~/.fonts.conf then it has the same effect. (If you already have a ~/.fonts.conf then you’ll want to merge them together – copy everything inside <fontconfig>...</fontconfig> from 70-force-bitmaps.conf and put it just before </fontconfig> in ~/.fonts.conf)