glibc (2.38)
1 #ifndef __A_OUT_GNU_H__
2 # error "Never use <bits/a.out.h> directly; include <a.out.h> instead."
3 #endif
4
5 #ifdef __x86_64__
6
7 /* Signal to users of this header that this architecture really doesn't
8 support a.out binary format. */
9 #define __NO_A_OUT_SUPPORT 1
10
11 #endif