netbsd compile failure with at-func.c

[Pádraig Brady]

It seems readlink is already a defined to __readlink_alias or something,
so when AT_FUNC_F1 is 'readlink', the following expansion will fail

# define CALL_FUNC(F) (AT_FUNC_F1 (F AT_FUNC_POST_FILE_ARGS))

i.e. CALL_FUNC (file) should be expanded to:
  readlink (file , buf, len)
but is just expanded to
  readlink

later,
Pádraig.