/usr/m68k-linux-gnu/include/bits/endian.h is in libc6-dev-m68k-cross 2.24-10cross1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 | /* m68k is big-endian. */
#ifndef _ENDIAN_H
# error "Never use <bits/endian.h> directly; include <endian.h> instead."
#endif
#define __BYTE_ORDER __BIG_ENDIAN
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