Merge branch 'master' into jgrpp

# Conflicts:
#	.gitignore
#	CMakeLists.txt
#	src/3rdparty/optional/optional.hpp
#	src/group_cmd.cpp
#	src/industry_cmd.cpp
#	src/misc_gui.cpp
#	src/video/sdl2_v.cpp

src/network/core/udp.cpp

@@ -164,6 +164,9 @@ void NetworkUDPSocketHandler::ReceivePackets()
 			/* Did we get the bytes for the base header of the packet? */
 			if (nbytes <= 0) break;    // No data, i.e. no packet
 			if (nbytes <= 2) continue; // Invalid data; try next packet
+#ifdef __EMSCRIPTEN__
+			client_len = FixAddrLenForEmscripten(client_addr);
+#endif
 
 			NetworkAddress address(client_addr, client_len);
 			p.PrepareToRead();