endian: Be able to detect endian on GNU and BSD

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

0 files changed, 0 insertions, 0 deletions