am 7d8febcb: am 56849da6: Merge "[MIPS] Import signal.h from bionic. This version fixes the warning emitted by the toolchain"

* commit '7d8febcb1a8c2c0b5a77e6d78c7637433a83071c':
  [MIPS] Import signal.h from bionic. This version fixes the warning emitted by the toolchain