Change _POSIX_CPUTIME macro to make it compitable with glibc.

Change-Id: I7a8dbb74bd622693c9fef60bd779687207517b7d
diff --git a/libc/include/machine/posix_limits.h b/libc/include/machine/posix_limits.h
index 25887be..4ffe421 100644
--- a/libc/include/machine/posix_limits.h
+++ b/libc/include/machine/posix_limits.h
@@ -41,7 +41,7 @@
 #define _POSIX_CHILD_MAX            25
 #define _POSIX_CHOWN_RESTRICTED     1  /* yes, chown requires appropriate privileges */
 #define _POSIX_CLOCK_SELECTION      200809L
-#define _POSIX_CPUTIME              200809L
+#define _POSIX_CPUTIME              0  /* Use sysconf to detect support at runtime. */
 #define _POSIX_DELAYTIMER_MAX       32
 #define _POSIX_FSYNC                200809L  /* fdatasync() supported */
 #define _POSIX_HOST_NAME_MAX        255
@@ -90,7 +90,7 @@
 #define _POSIX_THREADS              200809L  /* we support threads */
 #define _POSIX_THREAD_ATTR_STACKADDR  200809L
 #define _POSIX_THREAD_ATTR_STACKSIZE  200809L
-#define _POSIX_THREAD_CPUTIME       200809L
+#define _POSIX_THREAD_CPUTIME       0  /* Use sysconf to detect support at runtime. */
 #define _POSIX_THREAD_DESTRUCTOR_ITERATIONS 4
 #define _POSIX_THREAD_KEYS_MAX      128
 #define _POSIX_THREAD_PRIORITY_SCHEDULING 200809L