am 7eaa4dc2: Merge "Link against Mac OSX 10.5 SDK if building on 10.6." into gingerbread

Merge commit '7eaa4dc2fbc3d7b3d8a0a2576a6fc14507e176a8' into gingerbread-plus-aosp

* commit '7eaa4dc2fbc3d7b3d8a0a2576a6fc14507e176a8':
  Link against Mac OSX 10.5 SDK if building on 10.6.