time.h: Add CLOCK_TAI

Added in kernel in kernel 3.10 in
1ff3c9677bff ("timekeeping: Add CLOCK_TAI clockid")

NOTE: CLOCK_SGI_CYCLE was not added, as it has been lately removed.

Signed-off-by: Petr Vorel <petr.vorel@gmail.com>

libc/sysdeps/linux/common/bits/time.h

@@ -65,6 +65,8 @@
 #   define CLOCK_REALTIME_ALARM		8
 /* Like CLOCK_BOOTTIME but also wakes suspended system.  */
 #   define CLOCK_BOOTTIME_ALARM		9
+/* Like CLOCK_REALTIME but in International Atomic Time.  */
+# define CLOCK_TAI			11
 
 /* Flag to indicate time is absolute.  */
 #   define TIMER_ABSTIME		1