am 5d4cb156: am ec97c3f0: Merge "asm/sigcontext.h is required to build unwind-dw2.c in gcc-4.9."

* commit '5d4cb15610e91c99b062589e6297d423ed2e1176':
  asm/sigcontext.h is required to build unwind-dw2.c in gcc-4.9.