title: How do I convert NSString with Hexvalue to binary char*?
body: <p>I have a long hex value stored as a NSString, something like:</p>
  
  <p>c12761787e93534f6c443be73be31312cbe343816c062a278f3818cb8363c701</p>
  
  <p>How do I convert it back into a binary value stored as a char*</p>