Darwin/Mac OS host rust compilation fixes

- Don't pass `--as-needed` to the linker on Mac OS which is unsupported
  there
- Use `--force_load` rather than `--Wl,--whole-archive` on Mac OS
- Scan `rustc`'s linker arguments for `-dylib` and `-dynamiclib`, which
  it can use instead of `-shared` on Mac OS:
  https://github.com/rust-lang/rust/blob/7bd81ee1902c049691d0a1f03be5558bee51d100/compiler/rustc_codegen_ssa/src/back/linker.rs#L319

Test: m libhalf serde_derive
Bug: 291164566
Change-Id: Iecd6c2532fa31c9476834f49b109de98cbd2dccf