string: add to_upper overload for char arrays

string.hpp

@@ -63,6 +63,14 @@ namespace cruft {
     }
 
 
+    template <std::size_t N>
+    inline std::string
+    to_upper (char const (&val)[N])
+    {
+        return to_upper (std::string_view (val));
+    }
+
+
     /// Convert the provided string to all upper case
     inline std::string
     to_upper (std::string &&val)