5261 libm should stop using synonyms.h

*** 25,35 ****
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak atanh = __atanh
  
  /* INDENT OFF */
  /*
   * atanh(x)
   * Code originated from 4.3bsd.
--- 25,35 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __atanh = atanh
  
  /* INDENT OFF */
  /*
   * atanh(x)
   * Code originated from 4.3bsd.
*** 49,59 ****
   *      atanh(+-1) is +-INF with signal.
   */
  /* INDENT ON */
  
  #include "libm.h"
- #include "libm_synonyms.h"
  #include "libm_protos.h"
  #include <math.h>
  
  double
  atanh(double x) {
--- 49,58 ----