Add flex

Partial cherry pick of:
959ea284c41b1be5283f9eca421f1124c1ff5100 Update build-tools to ab/4801238

Change-Id: I33f00e915bf008698a737dc1a4d6f4854b8aa772
2 files changed
tree: 425e8d5f5c676275a3270f2a48d8ae32ba050b1b
  1. common/
  2. darwin-x86/
  3. linux-x86/
  4. build-prebuilts.sh
  5. manifest.xml
  6. OWNERS