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 log1pl = __log1pl
  
  /*
   * log1pl(x)
   * Kahan's trick based on log(1+x)/x being a slow varying function.
   */
--- 25,35 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __log1pl = log1pl
  
  /*
   * log1pl(x)
   * Kahan's trick based on log(1+x)/x being a slow varying function.
   */