Another thing - some people use VMs to play (or at least test DF, mods, etc.), and I know some people choose to use 32-bit OSes because they tend to require less memory to virtualize, at least sometimes. (It doesn't make a
huge difference when running large worlds in DF, but it does make a difference, although there probably aren't a lot of people doing that.)
I assume my SDL is 32-bit specific as well.
There are 64-bit versions here (SDL 1.2 and versions of SDL_image and SDL_ttf that work with SDL 1.2):
https://www.libsdl.org/download-1.2.phphttps://www.libsdl.org/projects/SDL_image/release-1.2.htmlhttps://www.libsdl.org/projects/SDL_ttf/release-1.2.htmlYou'll have to update the Linux and Mac libraries too - the current Linux one is just i386 (32-bit), and the OS X one is i386 and PowerPC, neither of which will work with a 64-bit DF.
In theory, changing -m32 to -m64 (or adding -m64) in the compiler flags should work when it comes to compiling a 32-bit DF with GCC, but there will probably be many linker errors as a result.
I also recommend OpenAL, mainly because it's used already on Linux and comes with the system on OS X (and is open-source and maintained!). It might be a good idea to distribute it anyway, though, since I don't know exactly which versions of which OSes distribute it by default.