official source tarball (NOT git)

[Henrik]

There is one very good reason to include them - most contributors, including me, develop on Windows and there's no sane dependency management there. Sorry about that, but there's not really any way around it. I can't require everyone to manually install all this stuff to build.

Also, the mentioned libraries are all very small and I don't find them a nuisance to have them in the git, it's not like we're gonna upgrade them all the time.