This is the diff for trailer hacks, which can be used to record the game at a constant framerate.
Some of this is splittable and committable, some of this isn't. Ideally, in the farther future, this will be supported.
Does not include the library files themselves for libJPEG.
Rebased from https://github.com/elexis1/0ad/tree/trailerhacks_a23