title: Where has simd matrix_linear_combination been gone in iOS11?
body: <pre><code> let m = matrix_linear_combination(alpha, v1, 1-alpha, v0)
  </code></pre>
  
  <p>matrix_linear_combination now generates "Use of unresolved identifier 'matrix_linear_combination'" error.</p>
  
  <p>Any existing replacement?</p>
  
  <p>PS : Should I clarify I already import simd and that there was no issue in iOS10/Swift 3).</p>