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 cexpl = __cexpl
  
  #include "libm.h"               /* expl/isinfl/iszerol/scalbnl/sincosl */
  #include "complex_wrapper.h"
  
  extern int isinfl(long double);
--- 25,35 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __cexpl = cexpl
  
  #include "libm.h"               /* expl/isinfl/iszerol/scalbnl/sincosl */
  #include "complex_wrapper.h"
  
  extern int isinfl(long double);