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 atanl = __atanl
  
  /*
   * atanl(x)
   * Table look-up algorithm
   * By K.C. Ng, March 9, 1989
--- 25,35 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __atanl = atanl
  
  /*
   * atanl(x)
   * Table look-up algorithm
   * By K.C. Ng, March 9, 1989