plumb glibc clock_get interfaces to irt

sysdeps/nacl/irt_syscalls.h

 #ifndef _IRT_SYSCALLS_H
 #define _IRT_SYSCALLS_H
 
 #include <sys/types.h>
 #include <stddef.h>
 #include <fcntl.h>
 #include <time.h>
 
 #include <nacl_stat.h>
 
@@ skipping 56 matching lines @@
 extern int (*__nacl_irt_cond_broadcast) (int cond_handle);
 extern int (*__nacl_irt_cond_wait) (int cond_handle, int mutex_handle);
 extern int (*__nacl_irt_cond_timed_wait_abs) (int cond_handle, int mutex_handle,
                                               const struct timespec *abstime);
 
 extern int (*__nacl_irt_tls_init) (void *tdb);
 extern void *(*__nacl_irt_tls_get) (void);
 
 extern int (*__nacl_irt_open_resource) (const char* file, int *fd);
 
+extern int (*__nacl_irt_clock_getres) (clockid_t clk_id, struct timespec *res);
+extern int (*__nacl_irt_clock_gettime) (clockid_t clk_id, struct timespec *tp);
+
 #ifdef _LIBC
 void init_irt_table (void) attribute_hidden;
 #endif
 #endif
 
 #if defined(_LIBC) || defined (__need_emulated_syscalls)
 #ifndef _IRT_EMULATED_SYSCALLS_H
 #define _IRT_EMULATED_SYSCALLS_H 1
 
 #ifndef _LINUX_TYPES_H
@@ skipping 43 matching lines @@
 struct robust_list_head
 {
   void *list;
   long int futex_offset;
   void *list_op_pending;
 };
 #endif
 
 #endif
 #endif