Just passing the enum debug on to the enum display function.

This should probably be changed later, but for now it will work alright.

src/c_enum.rs

@@ -89,7 +89,7 @@ macro_rules! c_enum
       {
          fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result
          {
-            write!(f, "{}", self.to_str())
+            ::std::fmt::Display::fmt(self, f)
          }
       }