diff --git a/net.c b/net.c
index 422ae3bc..5aad409d 100644
--- a/net.c
+++ b/net.c
@@ -10,7 +10,11 @@
 
 #include <ctype.h>
 #include <stdio.h>
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#elif HAVE_SYS_UNISTD_H
+#include <sys/unistd.h>
+#endif
 #include <sys/types.h>
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
diff --git a/pdu.c b/pdu.c
index 0636a4bf..82854ad7 100644
--- a/pdu.c
+++ b/pdu.c
@@ -83,7 +83,11 @@ coap_pdu_t *
 coap_new_pdu() {
   coap_pdu_t *pdu;
   
+#ifndef WITH_CONTIKI
   pdu = coap_pdu_init(0, 0, ntohs(COAP_INVALID_TID), COAP_MAX_PDU_SIZE);
+#else /* WITH_CONTIKI */
+  pdu = coap_pdu_init(0, 0, uip_ntohs(COAP_INVALID_TID), COAP_MAX_PDU_SIZE);
+#endif /* WITH_CONTIKI */
 
 #ifndef NDEBUG
   if (!pdu)