Add TEMP_FAILURE_RETRY macro for darwin

Darwin doesn't define the TEMP_FAILURE_RETRY macro in unistd.h so we
need to add it everywhere. Joy!

(cherry picked from commit ec90f1dc11488f0ab8a25a9159965b4ae3c4ca88)

Change-Id: Ida554fc65193672cc4616dec79e6282e06cc1b28
1 file changed