Right way to deploy an SDL app to Steam? Linux, Mac, Windows.

I have an SDL game that I have deployed on Steam. Currently I am deploying for Linux and Windows and plan to deploy for Mac later.

Recently when I deployed on Linux I noticed that the game wont run because SDL_mixer is missing. From what I understand Steam games should have access to SDL out of the box?

My Linux test machine has SDL2, SDL2_image and SDL2_ttf installed. Are these libraries installed automatically when Steam is installed?

Any ideas on why I’m missing SDL2_mixer on my Linux test machine?

My Linux distribution has only two objects
mygame (executable)
assets (graphics assets folder)

My Windows distrubution has:
mygame.exe (executable)
assets (graphics assets folder)

(sdl)
SDL2.dll
SDL2_image.dll
SDL2_mixer.dll
SDL2_ttf.dll

libFLAC-8.dll
libfreetype-6.dll
libgcc_s_seh-1.dll
libjpeg-9.dll
libmodplug-1.dll
libmpg123-0.dll
libogg-0.dll
libopus-0.dll
libopusfile-0.dll
libpng16-16.dll
libtiff-5.dll
libvorbis-0.dll
libvorbisfile-3.dll
libwebp-7.dll
zlib1.dll

(mingw64)
libgcc_s_seh-1.dll
libstdc+±6.dll
libwinpthread-1.dll

I’m using VS Code for both Linux and Windows. On Linux I’m building with g++ and on Windows with MingW64.

I’ve done a little research online and it sounds like dynamic linking is the best way to go. I’m still having trouble understanding the best/proper way to deploy my game on Steam and hope you may be able to provide some insights.

Some other questions I have:
Should I be using the steam-runtime to build? I’m still a little fuzzy on what the steam-runtime can offer.
Is it correct to be including all these DLL’s in the Windows deployment or is there a better way on Windows?

Getting Started with Linux Game Development (Steam Dev Days 2014) - YouTube (Getting Started with Linux Game Development (Steam Dev Days 2014))
Running SDL2 App on Mac/Linux, that don't have SDL2 installed - static linking? (CMake, CLion)
GitHub - ValveSoftware/steam-runtime: A runtime environment for Steam applications
SDL2/Installation - SDL Wiki
Documentation Home Page (Steamworks Documentation)

I haven’t done steam development yet, but looking at your list of included libs, I’m not seeing the shared object (.so) files for linux. (.dll) is Windows specific.

Either you will need to build SDL on a Linux machine, or link to whatever Steam provides. I’m assuming that Steam has some level of sand-boxing that prevents you from linking to the libs on the client’s machine?
You should also be able to find the *.so files in /usr/lib folder of your Linux system.

AFAIK no, Steam does not install SDL_Mixer. Yes, you should to link to the Steam runtime and use the Steam-provided version of SDL. Dunno if Steam provides their own build of SDL_Mixer (doubtful) but if not you’ll need to ship your own version of it.

Generally speaking, if you’re shipping something for Linux that isn’t packaged with/by the distribution, you don’t want to rely on the distribution libraries. They can be incredibly old, or may ship a new version that has regressions that blow up your app, and generally it’s not very user friendly to tell your users they need to go install some packages before they can play your game. Build and ship your own (they don’t have to be statically linked, either). If you’re building for Steam, use their build of something when available.