5261 libm should stop using synonyms.h

*** 28,38 ****
  
          .file "ilogb.s"
  
  #include "libm.h"
  LIBM_ANSI_PRAGMA_WEAK(ilogb,function)
- #include "libm_synonyms.h"
  #include "xpg6.h"
  
          .data
          .align  8
  two52:  .long   0x0,0x43300000  / 2**52
--- 28,37 ----