consider not hard-coding lib names

[lumenkeyes]

src/androidbuild/apk.zig's installAPK method renames all artifacts to libmain.so when adding them to the APK. This is not necessary. For native activities, for example, the lib name can be specified in the activity metadata anyway. This behaviour is also undesirable if a user intends to add multiple libraries. Each Step.Compile's name field could be used instead.

[silbinarywolf]

I'm happy to revisit the choice if there's a use-case for it, however it's worth noting it was originally put in place so that the library would work out of the box with SDL2/SDL3.

I'm open to a PR to stop this automatic rename from occurring as long as the relevant SDL2 example is updated to:

• Still run (not just compiles, runs on an Android emu)
• Has a comment saying "main" is the library name given so it'll just work with the SDLActivity.java implementation.