Add clock_settime and clock_nanosleep.

Add the missing prototypes, fix the existing prototypes to use clockid_t
rather than int, fix clock_nanosleep's failure behavior, and add simple
tests.

Bug: 17644443
Bug: https://code.google.com/p/android/issues/detail?id=77372
Change-Id: I03fba369939403918abcabae9551a7123953d780
Signed-off-by: Haruki Hasegawa <h6a.h4i.0@gmail.com>
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 47b7ef8..866671d 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -202,9 +202,9 @@
 int           settimeofday(const struct timeval*, const struct timezone*)   all
 clock_t       times(struct tms*)       all
 int           nanosleep(const struct timespec*, struct timespec*)   all
-int           clock_settime(clockid_t clk_id, const struct timespec* tp)  all
-int           clock_getres(clockid_t clk_id, struct timespec* res)   all
-int           clock_nanosleep(clockid_t clock_id, int flags, const struct timespec* req, struct timespec* rem)  all
+int           clock_settime(clockid_t, const struct timespec*)  all
+int           clock_getres(clockid_t, struct timespec*)   all
+int           __clock_nanosleep:clock_nanosleep(clockid_t, int, const struct timespec*, struct timespec*)  all
 int           getitimer(int, const struct itimerval*)   all
 int           setitimer(int, const struct itimerval*, struct itimerval*)  all
 int           __timer_create:timer_create(clockid_t clockid, struct sigevent* evp, __kernel_timer_t* timerid)    all