The app store master is based on
nop90's old sdl1 port which has been
removed but not yet replaced. Pacman only has an SDL2 package. Ironically, I was originally using SDL2 but switched to SDL1 since that was the only package available at the time.
I made a new branch for the SDL2 port here:
https://github.com/vgmoose/appstorenx/tree/sdl2 (also contains an updated readme for what to install with Pacman). However... it's not drawing graphics/text yet (even on PC, it's not) and I haven't had time to investigate why it's not working. If you're going to move forward, I would recommend helping getting the SDL2 port working, as that's a better solution than using SDL1 (plus libtransistor also supports SDL2).
For more info see this issue:
https://github.com/vgmoose/appstorenx/issues/6 If you do end up using the old sdl1 code, you might have to downgrade the libnx/devkitA64 versions as well.
I'm interested in this, but I feel like it may not be necessary in the future. Which apps do you know don't work on the latest firmware? (and we can make a note of it, or try to update them).