am 51976326: libc: Fix sem_post() implementation to wake up all waiting threads.

Merge commit '519763265ec0b634bd9c264a0aca034882458ecc' into gingerbread-plus-aosp

* commit '519763265ec0b634bd9c264a0aca034882458ecc':
  libc: Fix sem_post() implementation to wake up all waiting threads.