5261 libm should stop using synonyms.h

*** 42,52 ****
   * Special cases:
   *      if x is NaN, return x itself;
   *      if |x|>1, return NaN with invalid signal.
   */
  
! #pragma weak acosl = __acosl
  
  #include "libm.h"
  
  static const long double zero = 0.0L, one = 1.0L;
  
--- 42,52 ----
   * Special cases:
   *      if x is NaN, return x itself;
   *      if |x|>1, return NaN with invalid signal.
   */
  
! #pragma weak __acosl = acosl
  
  #include "libm.h"
  
  static const long double zero = 0.0L, one = 1.0L;