small cleanup of #ifdefs in BindListenPort()

- SO_NOSIGPIPE isn't available on WIN32 so merge the 2 non-WIN32 blocks
- use predefined names from header for IPV6_PROTECTION_LEVEL and
  PROTECTION_LEVEL_UNRESTRICTED

src/net.cpp

@@ -36,6 +36,17 @@
 #define MSG_NOSIGNAL 0
 #endif
 
+// Fix for ancient MinGW versions, that don't have defined these in ws2tcpip.h.
+// Todo: Can be removed when our pull-tester is upgraded to a modern MinGW version.
+#ifdef WIN32
+#ifndef PROTECTION_LEVEL_UNRESTRICTED
+#define PROTECTION_LEVEL_UNRESTRICTED 10
+#endif
+#ifndef IPV6_PROTECTION_LEVEL
+#define IPV6_PROTECTION_LEVEL 23
+#endif
+#endif
+
 using namespace std;
 using namespace boost;
 
@@ -1587,18 +1598,16 @@ bool BindListenPort(const CService &addrBind, string& strError)
         return false;
     }
 
+#ifndef WIN32
 #ifdef SO_NOSIGPIPE
     // Different way of disabling SIGPIPE on BSD
     setsockopt(hListenSocket, SOL_SOCKET, SO_NOSIGPIPE, (void*)&nOne, sizeof(int));
 #endif
-
-#ifndef WIN32
     // Allow binding if the port is still in TIME_WAIT state after
-    // the program was closed and restarted.  Not an issue on windows.
+    // the program was closed and restarted. Not an issue on windows!
     setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (void*)&nOne, sizeof(int));
 #endif
 
-
 #ifdef WIN32
     // Set to non-blocking, incoming connections will also inherit this
     if (ioctlsocket(hListenSocket, FIONBIO, (u_long*)&nOne) == SOCKET_ERROR)
@@ -1622,10 +1631,8 @@ bool BindListenPort(const CService &addrBind, string& strError)
 #endif
 #endif
 #ifdef WIN32
-        int nProtLevel = 10 /* PROTECTION_LEVEL_UNRESTRICTED */;
-        int nParameterId = 23 /* IPV6_PROTECTION_LEVEl */;
-        // this call is allowed to fail
-        setsockopt(hListenSocket, IPPROTO_IPV6, nParameterId, (const char*)&nProtLevel, sizeof(int));
+        int nProtLevel = PROTECTION_LEVEL_UNRESTRICTED;
+        setsockopt(hListenSocket, IPPROTO_IPV6, IPV6_PROTECTION_LEVEL, (const char*)&nProtLevel, sizeof(int));
 #endif
     }