Index: /trunk/src/VBox/Devices/Network/slirp/slirp.h
===================================================================
--- /trunk/src/VBox/Devices/Network/slirp/slirp.h	(revision 30217)
+++ /trunk/src/VBox/Devices/Network/slirp/slirp.h	(revision 30218)
@@ -78,4 +78,14 @@
 # include <iphlpapi.h>
 
+/* We don't want the errno.h versions of these error defines. */
+# if defined(_MSC_VER) && _MSC_VER >= 1600
+#  include <errno.h>
+#  undef EWOULDBLOCK
+#  undef EINPROGRESS
+#  undef ENOTCONN
+#  undef EHOSTUNREACH
+#  undef ENETUNREACH
+#  undef ECONNREFUSED
+# endif
 # define EWOULDBLOCK WSAEWOULDBLOCK
 # define EINPROGRESS WSAEINPROGRESS