Handle dependencies

* Only build CompressingStream and DecompressingStream when the
  AEMU_BASE_USE_LZ4 build option is enabled, and use the lz4 dependency
  provided by the caller.
* Do not guard lz4 code in both CompressingStream and
  DecompressingStream.

Bug: b/256177310
Change-Id: I87491c347a3270186a2ab15101157cd17eb0ae0c
7 files changed