5261 libm should stop using synonyms.h

*** 25,36 ****
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma weak atan2pil = __atan2pil
- 
  #include "libm.h"
  
  /*
   * atan2pil(y,x) = atan2l(y, x) / pi
   */
--- 25,34 ----