title: "Too many positionals passed" in NativeCall sub binding
body: <p>I have this defined: </p>
  
  <pre><code>use NativeCall;
  
  unit module kazmath;
  
  class mat4 is repr('CStruct') {
      HAS num32 @.mat[16] is CArray;
  }
  
  sub kmMat4Fill( mat4 $mat, num32 @filler ) returns mat4 is native('kazmath')
                                              is export {*}
  </code></pre>
  
  <p>The  function to bind is <a href="https://github.com/Kazade/kazmath/blob/master/kazmath/mat4.h#L60" rel="noreferrer">defined here</a>:</p>
  
  <pre><code>kmMat4* kmMat4Fill(kmMat4* pOut, const kmScalar* pMat);
  </code></pre>
  
  <p>And the error returned is:</p>
  
  <pre><code>Too many positionals passed; expected 2 arguments but got 3
  </code></pre>
  
  <p>I really can't figure this out. </p>