Enable process and thread CPU time clocks

sysdeps/nacl/clock_gettime.c

Index: sysdeps/nacl/clock_gettime.c
diff --git a/sysdeps/nacl/clock_gettime.c b/sysdeps/nacl/clock_gettime.c
index 4d6536279701833521e63baf9686cbe4a3b640dd..73660cf9c414fffb35464ebe487f7c293d9fa3a5 100644
--- a/sysdeps/nacl/clock_gettime.c
+++ b/sysdeps/nacl/clock_gettime.c
@@ -3,9 +3,17 @@
 
 #include <irt_syscalls.h>
 
+/*
+ * Please note that we do not support the general case via the TCB
+ * (pthread_getcpuclockid) which means that CLOCK_THREAD_CPUTIME_ID
+ * will behave differently from pthread_getcpuclockid(pthread_self()).
+ */
+
 #define SYSDEP_GETTIME                                      \
   case CLOCK_REALTIME:                                      \
   case CLOCK_MONOTONIC:                                     \
+  case CLOCK_PROCESS_CPUTIME_ID:                            \
+  case CLOCK_THREAD_CPUTIME_ID:                             \
     {                                                       \
       int result = __nacl_irt_clock_gettime (clock_id, tp); \
       if (result != 0)                                      \
@@ -19,5 +27,6 @@
     break;
 
 #define HANDLED_REALTIME
+#define HANDLED_CPUTIME
 
 #include <sysdeps/unix/clock_gettime.c>