diff --git a/upnp/src/inc/unixutil.h b/upnp/src/inc/unixutil.h
index da46b58..30e4269 100644
--- a/upnp/src/inc/unixutil.h
+++ b/upnp/src/inc/unixutil.h
@@ -35,10 +35,13 @@
 /* Unix-specific network utilities */
 
 #include "UpnpInet.h"
+#include <errno.h>
 
 #ifdef WIN32
 	typedef int socklen_t;
-	#define EAFNOSUPPORT 97
+	#ifndef EAFNOSUPPORT	/* VS2010 has this defined */
+		#define EAFNOSUPPORT 97
+	#endif
 #else
 	#include <sys/time.h>
 	#include <sys/wait.h>
diff --git a/upnp/src/inc/upnputil.h b/upnp/src/inc/upnputil.h
index 7236d6d..76292f8 100644
--- a/upnp/src/inc/upnputil.h
+++ b/upnp/src/inc/upnputil.h
@@ -38,6 +38,7 @@
  */
 
 #include "upnp.h"
+#include <errno.h>
 
 /* usually used to specify direction of parameters in functions */
 #ifndef IN
@@ -122,7 +123,9 @@ void linecopylen(
 		#ifndef S_ISDIR
 			#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
 		#endif
-		#define EADDRINUSE		WSAEADDRINUSE
+		#ifndef EADDRINUSE		/* VS2010 has this defined */
+			#define EADDRINUSE		WSAEADDRINUSE
+		#endif
 		#define strcasecmp		stricmp
 		#define strncasecmp		strnicmp
 		#define sleep(a)		Sleep((a)*1000)