From 5d93db81d256d495e9e3bc4b54bdf805c072b6dd Mon Sep 17 00:00:00 2001
From: UnknownShadow200 <unknownshadow200@gmail.com>
Date: Fri, 28 May 2021 17:54:57 +1000
Subject: [PATCH] Fix multiplayer not working at all with old emscripten

---
 misc/buildbot.sh   |  2 +-
 src/Platform_Web.c | 15 +++++++++++----
 src/interop_web.js |  2 +-
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/misc/buildbot.sh b/misc/buildbot.sh
index a7c11da01..6b716ce5e 100644
--- a/misc/buildbot.sh
+++ b/misc/buildbot.sh
@@ -90,7 +90,7 @@ WEB_CC="/home/buildbot/emsdk/emscripten/1.38.31/emcc"
 build_web() {
   echo "Building web.."
   rm cc.js
-  $WEB_CC *.c -O1 -o cc.js -s WASM=0 -s LEGACY_VM_SUPPORT=1 -s ALLOW_MEMORY_GROWTH=1 -s ABORTING_MALLOC=0 --preload-file texpacks/default.zip -w
+  $WEB_CC *.c -O1 -o cc.js --js-library interop_web.js -s WASM=0 -s LEGACY_VM_SUPPORT=1 -s ALLOW_MEMORY_GROWTH=1 -s ABORTING_MALLOC=0 --preload-file texpacks/default.zip -w
   # so game loads textures from classicube.net/static/default.zip
   sed -i 's#cc.data#/static/default.zip#g' cc.js
   # fix mouse wheel scrolling page not being properly prevented
diff --git a/src/Platform_Web.c b/src/Platform_Web.c
index 8b9edc408..bc91a0ed3 100644
--- a/src/Platform_Web.c
+++ b/src/Platform_Web.c
@@ -22,10 +22,17 @@
 #include <sys/time.h>
 #include <stdio.h>
 
+/* Unfortunately, errno constants are different in some older emscripten versions */
+/*  (linux errno compared to WASI errno) */
+/* So just use the same numbers as interop_web.js (otherwise connecting always fail) */
+#define _EINPROGRESS  26
+#define _EAGAIN        6 /* same as EWOULDBLOCK */
+#define _EHOSTUNREACH 23
+
 const cc_result ReturnCode_FileShareViolation = 1000000000; /* TODO: not used apparently */
 const cc_result ReturnCode_FileNotFound     = ENOENT;
-const cc_result ReturnCode_SocketInProgess  = EINPROGRESS;
-const cc_result ReturnCode_SocketWouldBlock = EWOULDBLOCK;
+const cc_result ReturnCode_SocketInProgess  = _EINPROGRESS;
+const cc_result ReturnCode_SocketWouldBlock = _EAGAIN;
 const cc_result ReturnCode_DirectoryExists  = EEXIST;
 #include <emscripten.h>
 #include "Chat.h"
@@ -288,7 +295,7 @@ cc_result Socket_Connect(cc_socket s, const cc_string* ip, int port) {
 	res = -interop_SocketConnect(s, addr, port);
 
 	/* error returned when invalid address provided */
-	if (res == EHOSTUNREACH) return ERR_INVALID_ARGUMENT;
+	if (res == _EHOSTUNREACH) return ERR_INVALID_ARGUMENT;
 	return res;
 }
 
@@ -305,7 +312,7 @@ cc_result Socket_Read(cc_socket s, cc_uint8* data, cc_uint32 count, cc_uint32* m
 			data      += res; count -= res;
 		} else {
 			/* EAGAIN when no data available */
-			if (res == -EAGAIN) break;
+			if (res == -_EAGAIN) break;
 			return -res;
 		}
 	}
diff --git a/src/interop_web.js b/src/interop_web.js
index 61b14f2fe..0ab1e0f99 100644
--- a/src/interop_web.js
+++ b/src/interop_web.js
@@ -125,7 +125,7 @@ mergeInto(LibraryManager.library, {
   },
   interop_InitSockets: function() {
     window.SOCKETS = {
-      EBADF:-8,EISCONN:-30,ENOTCONN:-53,EAGAIN:-6,EWOULDBLOCK:-6,EHOSTUNREACH:-23,EINPROGRESS:-26,EALREADY:-7,ECONNRESET:-15,EINVAL:-28,ECONNREFUSED:-14,
+      EBADF:-8,EISCONN:-30,ENOTCONN:-53,EAGAIN:-6,EHOSTUNREACH:-23,EINPROGRESS:-26,EALREADY:-7,ECONNRESET:-15,EINVAL:-28,ECONNREFUSED:-14,
       sockets: [],
       
       createSocket:function() {