diff --git a/ports/unix/port/include/arch/cc.h b/ports/unix/port/include/arch/cc.h
index 3e77e65..477da85 100644
--- a/ports/unix/port/include/arch/cc.h
+++ b/ports/unix/port/include/arch/cc.h
@@ -62,6 +62,14 @@
 typedef __kernel_fd_set fd_set;
 #endif
 
+#if defined(LWIP_UNIX_MACH)
+/* sys/types.h and signal.h bring in Darwin byte order macros. pull the
+   header here and disable LwIP's version so that apps still can get
+   the macros via LwIP headers and use system headers */
+#include <sys/types.h>
+#define LWIP_DONT_PROVIDE_BYTEORDER_FUNCTIONS
+#endif
+
 struct sio_status_s;
 typedef struct sio_status_s sio_status_t;
 #define sio_fd_t sio_status_t*
diff --git a/ports/unix/port/netif/sio.c b/ports/unix/port/netif/sio.c
index 686b2cb..8653fc9 100644
--- a/ports/unix/port/netif/sio.c
+++ b/ports/unix/port/netif/sio.c
@@ -4,6 +4,14 @@
 #define _XOPEN_SOURCE 600
 #define _GNU_SOURCE
 
+/* build with Darwin C extensions not part of POSIX, i.e. FASYNC, SIGIO.
+   we can't use LWIP_UNIX_MACH because extensions need to be turned
+   on before any system headers (which are pulled in through cc.h)
+   are included */
+#if defined(__APPLE__)
+#define _DARWIN_C_SOURCE
+#endif
+
 #include "netif/sio.h"
 #include "netif/fifo.h"
 #include "lwip/debug.h"
diff --git a/ports/unix/port/netif/unixif.c b/ports/unix/port/netif/unixif.c
index c945383..db833f2 100644
--- a/ports/unix/port/netif/unixif.c
+++ b/ports/unix/port/netif/unixif.c
@@ -35,6 +35,7 @@
 #include <fcntl.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/uio.h>