[Web] Disable UNIX sockets

They are not supported anyway, emscripten has an emulation layer that
implements them over WebSocket/WebRTC, which is really surprising for
users, and also not very useful since we have proper WebSocket and
WebRTC support.

This can make the build smaller, if we also disable the UPNP module
(which will otherwise include a third party library referencing "socket"
thus forcing emscripten to include the compatibility layer)

drivers/unix/net_socket_posix.h

@@ -33,6 +33,8 @@
 
 #include "core/io/net_socket.h"
 
+#ifndef UNIX_SOCKET_UNAVAILABLE
+
 #if defined(WINDOWS_ENABLED)
 #include <winsock2.h>
 #include <ws2tcpip.h>
@@ -105,4 +107,6 @@ class NetSocketPosix : public NetSocket {
 	~NetSocketPosix();
 };
 
+#endif
+
 #endif // NET_SOCKET_POSIX_H

drivers/unix/os_unix.cpp

@@ -166,7 +166,9 @@ void OS_Unix::initialize_core() {
 	DirAccess::make_default<DirAccessUnix>(DirAccess::ACCESS_USERDATA);
 	DirAccess::make_default<DirAccessUnix>(DirAccess::ACCESS_FILESYSTEM);
 
+#ifndef UNIX_SOCKET_UNAVAILABLE
 	NetSocketPosix::make_default();
+#endif
 	IPUnix::make_default();
 	process_map = memnew((HashMap<ProcessID, ProcessInfo>));
 
@@ -175,7 +177,9 @@ void OS_Unix::initialize_core() {
 
 void OS_Unix::finalize_core() {
 	memdelete(process_map);
+#ifndef UNIX_SOCKET_UNAVAILABLE
 	NetSocketPosix::cleanup();
+#endif
 }
 
 Vector<String> OS_Unix::get_video_adapter_driver_info() const {

platform/web/detect.py

@@ -201,7 +201,7 @@ def configure(env: "SConsEnvironment"):
         sys.exit(255)
 
     env.Prepend(CPPPATH=["#platform/web"])
-    env.Append(CPPDEFINES=["WEB_ENABLED", "UNIX_ENABLED"])
+    env.Append(CPPDEFINES=["WEB_ENABLED", "UNIX_ENABLED", "UNIX_SOCKET_UNAVAILABLE"])
 
     if env["opengl3"]:
         env.AppendUnique(CPPDEFINES=["GLES3_ENABLED"])