scripts: Add safe-struct string copy function

Change-Id: Ibaff390c34901c143d86cf58cd64de881a419372
diff --git a/layers/generated/vk_safe_struct.h b/layers/generated/vk_safe_struct.h
index 63752c3..f3e35f4 100644
--- a/layers/generated/vk_safe_struct.h
+++ b/layers/generated/vk_safe_struct.h
@@ -37,6 +37,7 @@
 void *SafePnextCopy(const void *pNext);
 void FreePnextChain(const void *head);
 void FreePnextChain(void *head);
+const char *SafeStringCopy(const char *in_string);
 
 
 struct safe_VkApplicationInfo {