Add semaphore tests, fix sem_destroy.

Bug: https://code.google.com/p/android/issues/detail?id=76088
Change-Id: I4a0561b23e90312384d40a1c804ca64ee98f4066
diff --git a/libc/private/bionic_time_conversions.h b/libc/private/bionic_time_conversions.h
index 51f543f..cf0046a 100644
--- a/libc/private/bionic_time_conversions.h
+++ b/libc/private/bionic_time_conversions.h
@@ -39,6 +39,8 @@
 
 __LIBC_HIDDEN__ void timeval_from_timespec(timeval& tv, const timespec& ts);
 
+__LIBC_HIDDEN__ bool timespec_from_absolute_timespec(timespec& ts, const timespec& abs_ts, clockid_t clock);
+
 __END_DECLS
 
 #endif