libjpeg is a pain in the ass, especially due to Ubuntu shipping
libjpeg-turbo in jpeg8 mode as their default libjpeg, while every other
distro I checked (including debian!) ships libjpeg-turbo in jpeg6.2 mode
Thankfully stb_image.h exists - just a single header and it even
has a (much!) friendlier API.
It's not like Doom3 (or any of the mods I checked) actually use JPEGs,
but I'm sure if I'd drop support completely, someone would complain
(perhaps rightfully so).
