am 779c0a9a: am 491489bb: am 21ec779a: Add stack unwinding directives to atomic-android-arm.S.

Merge commit '779c0a9a7a9d21b031167c21ca32004c23af6de4'

* commit '779c0a9a7a9d21b031167c21ca32004c23af6de4':
  Add stack unwinding directives to atomic-android-arm.S.