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 sincosf = __sincosf
  
  /* INDENT OFF */
  /*
   * For |x| < pi/4, let z = x * x, and approximate sin(x) by
   *
--- 24,34 ----
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __sincosf = sincosf
  
  /* INDENT OFF */
  /*
   * For |x| < pi/4, let z = x * x, and approximate sin(x) by
   *