Is CLOCKS_MASK macro obsolete?

[Elliott, Robert (Servers)]

The CLOCKS_MASK macro in include/uapi/linux/time.h seems broken; it's ORing together
two numbered values, one of which is 0. Perhaps these clock IDs started as a bitmask?
CLOCKS_MASK doesn't appear to be used anywhere in the kernel; nor does the adjacent 
CLOCKS_MONO.

Should those macros be deleted?

Excerpt:
#define CLOCK_REALTIME                  0
#define CLOCK_MONOTONIC                 1
#define CLOCK_PROCESS_CPUTIME_ID        2
#define CLOCK_THREAD_CPUTIME_ID         3
#define CLOCK_MONOTONIC_RAW             4
#define CLOCK_REALTIME_COARSE           5
#define CLOCK_MONOTONIC_COARSE          6
#define CLOCK_BOOTTIME                  7
#define CLOCK_REALTIME_ALARM            8
#define CLOCK_BOOTTIME_ALARM            9
/*
 * The driver implementing this got removed. The clock ID is kept as a
 * place holder. Do not reuse!
 */
#define CLOCK_SGI_CYCLE                 10
#define CLOCK_TAI                       11

#define MAX_CLOCKS                      16
#define CLOCKS_MASK                     (CLOCK_REALTIME | CLOCK_MONOTONIC)
#define CLOCKS_MONO                     CLOCK_MONOTONIC