Add missing includes.

Change-Id: I06ea08400efa511e627be37a4fd70fbdfadea2e6
diff --git a/uncrypt/uncrypt.c b/uncrypt/uncrypt.c
index e619237..b90bd6b 100644
--- a/uncrypt/uncrypt.c
+++ b/uncrypt/uncrypt.c
@@ -42,6 +42,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <stdarg.h>
 #include <sys/types.h>
 #include <sys/stat.h>