Allow unsigned char in copy_memory_or_grant

Author: shravanrn

code/include/rlbox_stdlib.hpp

@@ -136,6 +136,7 @@ inline T_Wrap<T_Rhs*, T_Sbx> memset(rlbox_sandbox<T_Sbx>& sandbox,
 
 template<typename T>
 static constexpr bool can_type_be_memcopied =
+  std::is_same_v<unsigned char, std::remove_cv_t<T>> ||
   std::is_same_v<char, std::remove_cv_t<T>> || std::is_same_v<wchar_t, std::remove_cv_t<T>> ||
   std::is_same_v<float, std::remove_cv_t<T>> || std::is_same_v<double, std::remove_cv_t<T>> ||
   std::is_same_v<char16_t, std::remove_cv_t<T>> || std::is_same_v<short, std::remove_cv_t<T>>;