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 sin = __sin
  
  /* INDENT OFF */
  /*
   * sin(x)
   * Accurate Table look-up algorithm by K.C. Ng, May, 1995.
--- 24,34 ----
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __sin = sin
  
  /* INDENT OFF */
  /*
   * sin(x)
   * Accurate Table look-up algorithm by K.C. Ng, May, 1995.