diff --git a/libc/include/time.h b/libc/include/time.h
index 8867b32..e280e0a 100644
--- a/libc/include/time.h
+++ b/libc/include/time.h
@@ -103,6 +103,7 @@
 #define CLOCK_THREAD_CPUTIME_ID    3
 #define CLOCK_REALTIME_HR          4
 #define CLOCK_MONOTONIC_HR         5
+#define CLOCK_BOOTTIME             7
 
 extern int  timer_create(int, struct sigevent*, timer_t*);
 extern int  timer_delete(timer_t);