Rename target aarch64-android to aarch64-linux-android

[straight-shoota]

aarch64-linux-android is the canonical name (#16403 (comment)).

Closes #16403

[HertzDevil]

It needs to be a symlink for compatibility, because the directory name under src/lib_c is still determined by Crystal::Codegen::Target#os_name, instead of the normalized LLVM triple (which is why the special case for Android needs to be dropped as well so that it could use the whole environment part)

[ysbaddaden]

I guess we need the symlink for forward compatibility, but Crystal::Codegen::Target#os_name shall return linux-android now. It's sole use is to build the lib_c path.

[straight-shoota]

Symlink works. 👍

But if we change CrystalPath#add_target_path(codegen_target) to search for aarch64-linux-android we lose compatibility with older stdlib versions which do not have this path.

We could add a special case for android (if src/lib_c/aarch64-linux-android, does not exist, look for src/lib_c/aarch64-linux-android instead), or keep using the symlink.

[ysbaddaden]

Oh right, new compiler trying to build older stdlib 😮‍💨