Move Android ucontext.h out of third_party. am: 757aea1419 am: 5df34462eb am: 64c5e351cc
am: a6810ad96c

Change-Id: I6927e1decec5a57c1b2251ee83f4dc8eb45087c7
tree: ef89efcab51ef149dbe7fe3f758c8751a234a490
  1. LICENSE.TXT