Added compile-time flag to disable Discord SDK

In order to support ARM/Mac, discord must be disabled.
To disable compile with:
make DISCORD_SDK=0

Fixes #62

Makefile

@@ -48,8 +48,10 @@ EXT_OPTIONS_MENU ?= 1
 TEXTSAVES ?= 0
 # Load resources from external files
 EXTERNAL_DATA ?= 0
-# Enable Discord Rich Presence
+# Enable Discord Rich Presence (outdated, no longer supported)
 DISCORDRPC ?= 0
+# Enable Discord Game SDK (used for Discord server hosting)
+DISCORD_SDK ?= 1
 # Enable docker build workarounds
 DOCKERBUILD ?= 0
 
@@ -289,13 +291,17 @@ LEVEL_DIRS := $(patsubst levels/%,%,$(dir $(wildcard levels/*/header.h)))
 
 # Hi, I'm a PC
 SRC_DIRS := src src/engine src/game src/audio src/menu src/buffers actors levels bin data assets src/pc src/pc/gfx src/pc/audio src/pc/controller src/pc/fs src/pc/fs/packtypes
-SRC_DIRS += src/pc/network src/pc/network/packets src/pc/network/socket src/pc/network/discord
+SRC_DIRS += src/pc/network src/pc/network/packets src/pc/network/socket
 ASM_DIRS :=
 
 #ifeq ($(DISCORDRPC),1)
 #  SRC_DIRS += src/pc/discord
 #endif
 
+ifeq ($(DISCORD_SDK),1)
+  SRC_DIRS += src/pc/network/discord
+endif
+
 BIN_DIRS := bin bin/$(VERSION)
 
 ULTRA_SRC_DIRS := lib/src lib/src/math
@@ -425,6 +431,7 @@ RPC_LIBS :=
 #endif
 
 DISCORD_SDK_LIBS :=
+ifeq ($(DISCORD_SDK), 1)
   ifeq ($(WINDOWS_BUILD),1)
     DISCORD_SDK_LIBS := lib/discordsdk/discord_game_sdk.dll
   else ifeq ($(OSX_BUILD),1)
@@ -433,6 +440,7 @@ else ifeq ($(OSX_BUILD),1)
   else
     DISCORD_SDK_LIBS := lib/discordsdk/libdiscord_game_sdk.so
   endif
+endif
 
 # Automatic dependency files
 DEP_FILES := $(O_FILES:.o=.d) $(ULTRA_O_FILES:.o=.d) $(GODDARD_O_FILES:.o=.d) $(BUILD_DIR)/$(LD_SCRIPT).d
@@ -460,19 +468,18 @@ else
   CXX := emcc
 endif
 
-LD := $(CXX)
-
 #ifeq ($(DISCORDRPC),1)
-#  LD := $(CXX)
-#else ifeq ($(WINDOWS_BUILD),1)
-#  ifeq ($(CROSS),i686-w64-mingw32.static-) # fixes compilation in MXE on Linux and WSL
-#    LD := $(CC)
-#  else ifeq ($(CROSS),x86_64-w64-mingw32.static-)
-#    LD := $(CC)
-#  else
-#    LD := $(CXX)
-#  endif
-#endif
+ifeq ($(DISCORD_SDK),1)
+  LD := $(CXX)
+else ifeq ($(WINDOWS_BUILD),1)
+  ifeq ($(CROSS),i686-w64-mingw32.static-) # fixes compilation in MXE on Linux and WSL
+    LD := $(CC)
+  else ifeq ($(CROSS),x86_64-w64-mingw32.static-)
+    LD := $(CC)
+  else
+    LD := $(CXX)
+  endif
+endif
 
 ifeq ($(WINDOWS_BUILD),1) # fixes compilation in MXE on Linux and WSL
   CPP := cpp -P
@@ -621,6 +628,12 @@ endif
 #  CFLAGS += -DDISCORDRPC
 #endif
 
+# Check for Discord SDK option
+ifeq ($(DISCORD_SDK),1)
+  CC_CHECK += -DDISCORD_SDK
+  CFLAGS += -DDISCORD_SDK
+endif
+
 # Check for texture fix option
 ifeq ($(TEXTURE_FIX),1)
   CC_CHECK += -DTEXTURE_FIX
@@ -692,10 +705,14 @@ endif
 
 ifeq ($(WINDOWS_BUILD),1)
   LDFLAGS += -L"ws2_32" -lwsock32
+  ifeq ($(DISCORD_SDK),1)
     LDFLAGS += -Wl,-Bdynamic -ldiscord_game_sdk -Wl,-Bstatic
+  endif
 else
+  ifeq ($(DISCORD_SDK),1)
     LDFLAGS += -ldiscord_game_sdk -Wl,-rpath . -Wl,-rpath lib/discordsdk
   endif
+endif
 
 
 # End of LDFLAGS

src/menu/custom_menu.c

@@ -72,17 +72,23 @@ static void host_menu_draw_strings(void) {
 }
 
 static void host_menu_do_host(void) {
+#ifndef DISCORD_SDK
+    configNetworkSystem = 1;
+#endif
     if (configNetworkSystem == 0) {
         network_set_system(NS_DISCORD);
-    }
-    else {
+    } else {
         network_set_system(NS_SOCKET);
     }
     custom_menu_close_system();
 }
 
 static void host_menu_setting_network_system(void) {
+#ifdef DISCORD_SDK
     configNetworkSystem = (configNetworkSystem == 0) ? 1 : 0;
+#else
+    configNetworkSystem = 1;
+#endif
 }
 
 static void host_menu_setting_interaction(void) {

src/pc/configfile.c

@@ -321,6 +321,10 @@ void configfile_load(const char *filename) {
     }
 
     fs_close(file);
+
+#ifndef DISCORD_SDK
+    configNetworkSystem = 1;
+#endif
 }
 
 // Writes the config file to 'filename'

src/pc/network/network.c

@@ -3,7 +3,9 @@
 #include "object_fields.h"
 #include "object_constants.h"
 #include "socket/socket.h"
+#ifdef DISCORD_SDK
 #include "discord/discord.h"
+#endif
 #include "pc/configfile.h"
 #include "pc/debuglog.h"
 
@@ -11,7 +13,11 @@
 extern s16 sCurrPlayMode;
 
 enum NetworkType gNetworkType = NT_NONE;
+#ifdef DISCORD_SDK
 struct NetworkSystem* gNetworkSystem = &gNetworkSystemDiscord;
+#else
+struct NetworkSystem* gNetworkSystem = &gNetworkSystemSocket;
+#endif
 
 #define LOADING_LEVEL_THRESHOLD 10
 u8 networkLoadingLevel = 0;
@@ -27,7 +33,9 @@ struct ServerSettings gServerSettings = {
 void network_set_system(enum NetworkSystemType nsType) {
     switch (nsType) {
         case NS_SOCKET:  gNetworkSystem = &gNetworkSystemSocket; break;
+#ifdef DISCORD_SDK
         case NS_DISCORD: gNetworkSystem = &gNetworkSystemDiscord; break;
+#endif
         default: LOG_ERROR("Unknown network system: %d", nsType);
     }
 }

src/pc/network/network_player.h

@@ -10,6 +10,7 @@
 #define NETWORK_PLAYER_TIMEOUT 10
 
 enum NetworkPlayerType {
+    NPT_UNKNOWN,
     NPT_LOCAL,
     NPT_SERVER,
     NPT_CLIENT,