add a script to generate the sysroot

Example usage:
$ ./src/third_party/portage-prefix/setup_board --board bruteus
$ ./build/bruteus/build/bin/emerge android-base/zlib

BUG=b:20895978

Change-Id: I9a0d270e164703d775c69c570ac92976dad4f881
1 file changed
tree: 30f53af965e76d570644d69d99e1c86ffc83c636
  1. .gitignore
  2. etc/
  3. setup_board
  4. usr/
  5. wrapper.py