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 scalbl = __scalbl
  
  /*
   * scalbl(x,n): return x * 2^n by manipulating exponent.
   */
  
--- 25,35 ----
  /*
   * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
! #pragma weak __scalbl = scalbl
  
  /*
   * scalbl(x,n): return x * 2^n by manipulating exponent.
   */