diff --git a/libc/include/time.h b/libc/include/time.h
index 14066a1a1..5d1a0e268 100644
--- a/libc/include/time.h
+++ b/libc/include/time.h
@@ -109,7 +109,7 @@ extern long int  timezone;
 
 #define CLOCKS_PER_SEC     1000000
 
-extern clock_t   clock();
+extern clock_t   clock(void);
 
 /* BIONIC: extra linux clock goodies */
 extern int clock_getres(int, struct timespec *);