Added string.h.

diff --git a/dlls/ntdll/time.c b/dlls/ntdll/time.c
index 8a7296c..b749edc 100644
--- a/dlls/ntdll/time.c
+++ b/dlls/ntdll/time.c
@@ -10,6 +10,7 @@
 
 #include <ntddk.h>
 
+#include <string.h>
 #include <debug.h>
 #include <file.h>