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 signgam = __signgam
  
- #include "libm_synonyms.h"
  #include <math.h>
  
  int signgam = 0;
--- 25,34 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __signgam = signgam
  
  #include <math.h>
  
  int signgam = 0;