On GNU __BYTE_ORDER and __LITTLE_ENDIAN is defined and
the include is "endian.h" on FreeBSD it is "sys/endian.h"
and LITTLE_ENDIAN/_LITTLE_ENDIAN and BYTE_ORDER/_BYTE_ORDER
is defined.
Create a header file that defines OSMO_IS_LITTLE_ENDIAN
and OSMO_IS_BIG_ENDIAN and can be used as
#if OSMO_IS_LITTLE_ENDIAN
do_little_endian
#elif OSMO_IS_BIG_ENDIAN
do_big_endian
#else
#error "Unknown endian"
#endif
Holger Hans Peter Freyther