5261 libm should stop using synonyms.h

*** 25,38 ****
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak atanhl = __atanhl
  
  #include "libm.h"
- #include "libm_synonyms.h"
  
  #define GENERIC long double
  #define ATANH   atanhl
  
  /* ATANH(x)
--- 25,37 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __atanhl = atanhl
  
  #include "libm.h"
  
  #define GENERIC long double
  #define ATANH   atanhl
  
  /* ATANH(x)