Fix a couple of printf format warnings.

Also if we try to compile on an unsupported platform, emit some code
in portable_endian.h that at least has a chance of compiling, rather
than erroring out right away.

For #191.

src/iperf_udp.c

@@ -82,7 +82,7 @@ iperf_udp_recv(struct iperf_stream *sp)
         sp->packet_count = pcount;
     } else {
         sp->outoforder_packets++;
-	iperf_err(sp->test, "OUT OF ORDER - incoming packet = %llu and received packet = %d AND SP = %d", pcount, sp->packet_count, sp->socket);
+	iperf_err(sp->test, "OUT OF ORDER - incoming packet = %zu and received packet = %d AND SP = %d", pcount, sp->packet_count, sp->socket);
     }
 
     /* jitter measurement */
@@ -98,7 +98,7 @@ iperf_udp_recv(struct iperf_stream *sp)
     sp->jitter += (d - sp->jitter) / 16.0;
 
     if (sp->test->debug) {
-	fprintf(stderr, "packet_count %llu\n", sp->packet_count);
+	fprintf(stderr, "packet_count %d\n", sp->packet_count);
     }
 
     return r;

src/portable_endian.h

@@ -117,8 +117,10 @@
 
 #else
 
-#	error platform not supported
+#	warning platform not supported
+#	include <sys/endian.h>
 
 #endif
 
 #endif
+