We don't want GCC's fixincludes to touch our <stdio.h> because we
want to support multiple platform versions with one toolchain. Give
them a nice easy unambiguous string to look for.
Bug: http://code.google.com/p/android/issues/detail?id=73728
Change-Id: I15cb9a2c9eb0a44b0965dc2139f224f2b6e68ea1