5261 libm should stop using synonyms.h

*** 107,117 ****
   * The decimal values may be used, provided that the compiler will convert
   * from decimal to binary accurately enough to produce the hexadecimal values
   * shown.
   */
  
! #pragma weak log1pl = __log1pl
  
  #include "libm.h"
  
  extern const long double _TBL_logl_hi[], _TBL_logl_lo[];
  
--- 107,117 ----
   * The decimal values may be used, provided that the compiler will convert
   * from decimal to binary accurately enough to produce the hexadecimal values
   * shown.
   */
  
! #pragma weak __log1pl = log1pl
  
  #include "libm.h"
  
  extern const long double _TBL_logl_hi[], _TBL_logl_lo[];