5261 libm should stop using synonyms.h

*** 24,34 ****
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak catanf = __catanf
  
  #include "libm.h"
  #include "complex_wrapper.h"
  
  #if defined(__i386) && !defined(__amd64)
--- 24,34 ----
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __catanf = catanf
  
  #include "libm.h"
  #include "complex_wrapper.h"
  
  #if defined(__i386) && !defined(__amd64)