5261 libm should stop using synonyms.h

*** 25,36 ****
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
- #pragma weak sinpil = __sinpil
- 
  /*
   * long double sinpil(long double x),
   * return long double precision sinl(pi*x).
   *
   * Algorithm, 10/17/2002, K.C. Ng
--- 25,34 ----