player: increase warning level and fix a warning

sync/base.h

@@ -43,7 +43,15 @@ static inline int socket_poll(SOCKET socket)
 	fd_set fds;
 
 	FD_ZERO(&fds);
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable: 4127)
+#endif
 	FD_SET(socket, &fds);
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
 
 	return select(0, &fds, NULL, NULL, &to) > 0;
 }

sync_player.vcproj

@@ -166,7 +166,7 @@
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="1"
 				UsePrecompiledHeader="0"
-				WarningLevel="3"
+				WarningLevel="4"
 				DebugInformationFormat="4"
 			/>
 			<Tool