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 fegetprec = __fegetprec
! #pragma weak fesetprec = __fesetprec
  
- #include "fenv_synonyms.h"
  #include <fenv.h>
  #include <ucontext.h>
  #include <thread.h>
  #include "fex_handler.h"
  
--- 25,37 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __fegetprec = fegetprec
! #pragma weak __fesetprec = fesetprec
  
  #include <fenv.h>
  #include <ucontext.h>
  #include <thread.h>
  #include "fex_handler.h"