Fix build. New clang has stricter checking.

Change-Id: I1c8a826f41ed9fa503ce0545d85c198a5151ab6e
diff --git a/rsg_generator.c b/rsg_generator.c
index c0f82dc..c404c9c 100644
--- a/rsg_generator.c
+++ b/rsg_generator.c
@@ -1,6 +1,7 @@
 
 #include "spec.h"
 #include <stdio.h>
+#include <string.h>
 
 void printFileHeader(FILE *f) {
     fprintf(f, "/*\n");