Restore BYTE_ORDER on DARWIN The files matching grep "define _POSIX_C_SOURCE" src...

Restore BYTE_ORDER on DARWIN The files matching grep "define _POSIX_C_SOURCE" src/*.c on MacOSX do not compile: In file included from target_notification.c:60: collectd.h:172:3: error: #error "Cannot determine byte order"

See /usr/include/i386/endian.h:
 #if defined(KERNEL) || (!defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE))

 #define LITTLE_ENDIAN   __DARWIN_LITTLE_ENDIAN
 #define BIG_ENDIAN      __DARWIN_BIG_ENDIAN
 #define BYTE_ORDER      __DARWIN_BYTE_ORDER

Signed-off-by: Doug MacEachern <dougm@hyperic.com>
Signed-off-by: Florian Forster <octo@huhu.verplant.org>