Add rust::String(const char *, size_t) constructor
diff --git a/include/cxx.h b/include/cxx.h
index f211b3b..5a33a7a 100644
--- a/include/cxx.h
+++ b/include/cxx.h
@@ -29,6 +29,7 @@
 
   String(const std::string &);
   String(const char *);
+  String(const char *, size_t);
 
   String &operator=(const String &) noexcept;
   String &operator=(String &&) noexcept;