Kernel: Add basic nanosleep, only millisecond percision

libc/include/sys/syscall.h

@@ -51,6 +51,7 @@ __BEGIN_DECLS
 #define SYS_GET_PGID 44
 #define SYS_SET_PGID 45
 #define SYS_FCNTL 46
+#define SYS_NANOSLEEP 47
 
 __END_DECLS
 

libc/time.cpp

@@ -5,4 +5,9 @@
 int clock_gettime(clockid_t clock_id, struct timespec* tp)
 {
 	return syscall(SYS_CLOCK_GETTIME, clock_id, tp);
+}
+
+int nanosleep(const struct timespec* rqtp, struct timespec* rmtp)
+{
+	return syscall(SYS_NANOSLEEP, rqtp, rmtp);
 }