misc: Attempt to determine byte order in a cross-platform way

OSX does not provide an endian.h, use the other header files that
should define/include what we need. Also check that the byteorder
define is available.

openbsc/src/mgcp/mgcp_network.c

@@ -25,7 +25,6 @@
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <endian.h>
 #include <errno.h>
 
 #include <sys/socket.h>
@@ -40,6 +39,15 @@
 
 #warning "Make use of the rtp proxy code"
 
+/* attempt to determine byte order */
+#include <sys/types.h>
+#include <sys/param.h>
+#include <limits.h>
+
+#ifndef __BYTE_ORDER
+#error "__BYTE_ORDER should be defined by someone"
+#endif
+
 /* according to rtp_proxy.c RFC 3550 */
 struct rtp_hdr {
 #if __BYTE_ORDER == __LITTLE_ENDIAN

openbsc/src/rtp_proxy.c

@@ -19,7 +19,6 @@
  *
  */
 
-#include <endian.h>
 #include <errno.h>
 #include <unistd.h>
 #include <sys/socket.h>
@@ -37,6 +36,15 @@
 #include <openbsc/debug.h>
 #include <openbsc/rtp_proxy.h>
 
+/* attempt to determine byte order */
+#include <sys/types.h>
+#include <sys/param.h>
+#include <limits.h>
+
+#ifndef __BYTE_ORDER
+#error "__BYTE_ORDER should be defined by someone"
+#endif
+
 static LLIST_HEAD(rtp_sockets);
 
 /* should we mangle the CNAME inside SDES of RTCP packets? We disable