5261 libm should stop using synonyms.h

*** 28,38 ****
  
          .file "rintf.s"
  
  #include "libm.h"
  LIBM_ANSI_PRAGMA_WEAK(rintf,function)
- #include "libm_synonyms.h"
  
          ENTRY(rintf)
          flds    4(%esp)                 / load x
          movl    4(%esp),%eax            / eax <-- x
          andl    $0x7fffffff,%eax        / eax <-- |x|
--- 28,37 ----