5261 libm should stop using synonyms.h

*** 28,38 ****
  
          .file "fmodl.s"
  
  #include "libm.h"
  LIBM_ANSI_PRAGMA_WEAK(fmodl,function)
- #include "libm_synonyms.h"
  
          ENTRY(fmodl)
          fldt    24(%rsp)                / load arg y
          fldt    8(%rsp)                 / load arg x
  .mod_loop:
--- 28,37 ----