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 lround = __lround
  
  /*
   * lround(x) rounds its argument to the nearest integer, rounding ties
   * away from zero, and converts the result to a 32 bit signed integer.
   *
--- 25,35 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __lround = lround
  
  /*
   * lround(x) rounds its argument to the nearest integer, rounding ties
   * away from zero, and converts the result to a 32 bit signed integer.
   *