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 logf = __logf
  
  /*
   * Algorithm:
   *
   * Let y = x rounded to six significant bits.  Then for any choice
--- 24,34 ----
  /*
   * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __logf = logf
  
  /*
   * Algorithm:
   *
   * Let y = x rounded to six significant bits.  Then for any choice