LTO导致configure时的conftest失败

代码:
/* end confdefs.h.  */

/* Define pthread_attr_get_np to an innocuous variant, in case <limits.h> declares pthread_attr_get_np.

   For example, HP-UX 11i <limits.h> declares gettimeofday.  */

#define pthread_attr_get_np innocuous_pthread_attr_get_np



/* System header to define __stub macros and hopefully few prototypes,

    which can conflict with char pthread_attr_get_np (); below.

    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since

    <limits.h> exists even on freestanding compilers.  */



#ifdef __STDC__

# include <limits.h>

#else

# include <assert.h>

#endif



#undef pthread_attr_get_np



/* Override any gcc2 internal prototype to avoid an error.  */

#ifdef __cplusplus

extern "C"

{

#endif

/* We use char because int might match the return type of a gcc2

   builtin and then its argument prototype would still apply.  */

char pthread_attr_get_np ();

/* The GNU C library defines this for functions which it implements

    to always fail with ENOSYS.  Some functions are actually named

    something starting with __ and the normal name is an alias.  */

#if defined (__stub_pthread_attr_get_np) || defined (__stub___pthread_attr_get_np)

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#else

char (*f) () = pthread_attr_get_np;

#endif

#ifdef __cplusplus

}

#endif



int

main ()

{

return f != pthread_attr_get_np;

  ;

  return 0;

}