Add futimens.

Bug: 10239370
Change-Id: I518340084103dc339ef8a065d4837d6258a1381d
diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index c7715a3..10627b9 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -168,7 +168,8 @@
 
 # define UTIME_NOW      ((1l << 30) - 1l)
 # define UTIME_OMIT     ((1l << 30) - 2l)
-extern int utimensat (int fd, const char *path, const struct timespec times[2], int flags);
+extern int utimensat(int fd, const char *path, const struct timespec times[2], int flags);
+extern int futimens(int fd, const struct timespec times[2]);
 
 __END_DECLS