Haiku: Make network module compile on Haiku

Add the missing definition for IFF_RUNNING like
documented on http://ports.haiku-files.org/wiki/CommonProblems

Change-Id: Iea3fa224dc8e7e1e36674026efbb28289d2efa2a
Reviewed-by: Augustin Cavalier <waddlesplash@gmail.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>

src/network/kernel/qnetworkinterface_unix.cpp

@@ -58,6 +58,11 @@
 # define QT_NO_IPV6IFNAME
 #endif
 
+#ifdef Q_OS_HAIKU
+# include <sys/sockio.h>
+# define IFF_RUNNING 0x0001
+#endif
+
 #ifndef QT_NO_GETIFADDRS
 # include <ifaddrs.h>
 #endif