Fixes for error handling in NetChannel

- return the correct errno value instead of using -1

simgear/io/raw_socket.cxx

@@ -684,6 +684,15 @@ bool Socket::isNonBlockingError ()
 #endif
 }
 
+int Socket::errorNumber()
+{
+#if defined(WINSOCK)
+    return WSAGetLastError();
+#else
+    return errno;
+#endif
+}
+
 
 //////////////////////////////////////////////////////////////////////
 //

simgear/io/raw_socket.hxx

@@ -101,6 +101,7 @@ public:
   void setBroadcast ( bool broadcast ) ;
 
   static bool isNonBlockingError () ;
+  static int errorNumber();
 
   static int select ( Socket** reads, Socket** writes, int timeout ) ;
 } ;

simgear/io/sg_netChannel.cxx

@@ -114,7 +114,7 @@ NetChannel::send (const void * buffer, int size, int flags)
     write_blocked = true ;
     return 0;
   } else {
-    this->handleError (result);
+    this->handleError (errorNumber());
     close();
     return -1;
   }
@@ -134,7 +134,7 @@ NetChannel::recv (void * buffer, int size, int flags)
   } else if (isNonBlockingError ()) {
     return 0;
   } else {
-    this->handleError (result);
+    this->handleError (errorNumber());
     close();
     return -1;
   }
@@ -207,7 +207,7 @@ NetChannel::handleResolve()
         return 0;
     } else {
         // some other error condition
-        handleError (result);
+        handleError (errorNumber());
         close();
         return -1;
     }