Linux puskom-ProLiant-DL385-Gen10 5.4.0-150-generic #167~18.04.1-Ubuntu SMP Wed May 24 00:51:42 UTC 2023 x86_64

//usr/include/x86_64-linux-gnu/bits/a.out.h

 #ifndef __A_OUT_GNU_H__
# error "Never use <bits/a.out.h> directly; include <a.out.h> instead."
#endif

#ifdef __x86_64__

/* Signal to users of this header that this architecture really doesn't
   support a.out binary format.  */
#define __NO_A_OUT_SUPPORT 1

#endif