5261 libm should stop using synonyms.h

*** 24,35 ****
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma weak atan2pif = __atan2pif
- 
  #include "libm.h"
  
  static const double invpi = 0.3183098861837906715377675;
  
  float
--- 24,33 ----