Be more defensive in Qt5Network code.

It's possible, but rather unlikely, to build Qt5Network with
QT_NO_NETWORKINTERFACE, and still get around to building the
generic bearer. In that case, comment out the workaround
that needs an interface.

PR:		232784
Obtained from:	Max Steciuk

net/qt5-network/Makefile

@@ -2,7 +2,7 @@
 
 PORTNAME=	network
 DISTVERSION=	${QT5_VERSION}
-PORTREVISION=	3
+PORTREVISION=	4
 CATEGORIES=	net ipv6
 PKGNAMEPREFIX=	qt5-
 

net/qt5-network/files/patch-src_plugins_bearer_generic_qgenericengine.cpp

@@ -5,9 +5,9 @@ If getting the HW address succeeds, assume it's Ethernet. Tested
 with two Ethernet cards and a vlan (all of which have a MAC reported
 by ifconfig).
 
---- src/plugins/bearer/generic/qgenericengine.cpp.orig	2018-12-03 12:15:26.000000000 +0100
-+++ src/plugins/bearer/generic/qgenericengine.cpp	2018-12-23 12:42:48.095145000 +0100
-@@ -82,7 +82,7 @@
+--- src/plugins/bearer/generic/qgenericengine.cpp.orig	2018-12-03 11:15:26 UTC
++++ src/plugins/bearer/generic/qgenericengine.cpp
+@@ -82,7 +82,7 @@ using namespace ABI::Windows::Networking::Connectivity
  // needed as interface is used as parameter name in qGetInterfaceType
  #undef interface
  
@@ -16,7 +16,7 @@ by ifconfig).
  #include <sys/socket.h>
  #include <sys/ioctl.h>
  #include <net/if.h>
-@@ -139,6 +139,23 @@
+@@ -139,6 +139,23 @@ static QNetworkConfiguration::BearerType qGetInterface
  
      if (result >= 0 && request.ifr_hwaddr.sa_family == ARPHRD_ETHER)
          return QNetworkConfiguration::BearerEthernet;
@@ -40,3 +40,15 @@ by ifconfig).
  #elif defined(Q_OS_WINRT)
      ComPtr<INetworkInformationStatics> networkInfoStatics;
      HRESULT hr = GetActivationFactory(HString::MakeReference(RuntimeClass_Windows_Networking_Connectivity_NetworkInformation).Get(), &networkInfoStatics);
+@@ -231,9 +248,11 @@ static QNetworkConfiguration::BearerType qGetInterface
+ QGenericEngine::QGenericEngine(QObject *parent)
+ :   QBearerEngineImpl(parent)
+ {
++#ifndef QT_NO_NETWORKINTERFACE
+     //workaround for deadlock in __cxa_guard_acquire with webkit on macos x
+     //initialise the Q_GLOBAL_STATIC in same thread as the AtomicallyInitializedStatic
+     (void)QNetworkInterface::interfaceFromIndex(0);
++#endif
+ }
+ 
+ QGenericEngine::~QGenericEngine()