Features(Lualib/Lua(Jit)): Lua Version and Static Linking Support

### Eluna Module Updates: Lua Version and Static Linking Support

Recent updates to the **Eluna** module in **AzerothCore** introduce new configuration options to manage Lua versions and static linking:

- **`-DLUA_VERSION=luajit/lua52/lua53/lua54`**: Select the Lua version for the module, supporting LuaJIT, Lua 5.2, 5.3, or 5.4.
- **`-DLUA_STATIC=on/off`**: Configure whether Lua should be linked statically or dynamically.

These options allow flexible Lua integration, building on Eluna's existing capabilities to handle different Lua versions. The changes also improve compatibility and performance by enabling static linking where needed.

#### Integration with Eluna

This functionality extends Eluna's existing support for Lua compatibility, mainly in **ElunaCompat.cpp**, which handles Lua version-specific interactions. These updates enhance Eluna’s adaptability for various Lua configurations in **AzerothCore**.

CMakeLists.txt

@@ -0,0 +1,25 @@
+set(LUA_VERSION "lua52" CACHE STRING "Lua version to use")
+set_property(CACHE LUA_VERSION PROPERTY STRINGS luajit lua51 lua52 lua53 lua54)
+MESSAGE(STATUS "Lua version: ${LUA_VERSION}")
+
+# Avoid warning about DOWNLOAD_EXTRACT_TIMESTAMP in CMake 3.24:
+if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
+  cmake_policy(SET CMP0135 NEW)
+endif()
+
+option(LUA_STATIC "link lua statically" OFF)
+if (LUA_STATIC)
+  MESSAGE(STATUS "Lua linking: static")
+else()
+  MESSAGE(STATUS "Lua linking: dynamic")
+endif()
+
+if (LUA_VERSION MATCHES "luajit")
+  add_subdirectory(src/lualib/luajit)
+  set(LUAJIT_VERSION true)
+else()
+  add_subdirectory(src/lualib/lua)
+  set(LUAJIT_VERSION false)
+endif()
+
+set_target_properties(lualib PROPERTIES INTERFACE_COMPILE_DEFINITIONS LUAJIT_VERSION)

src/LuaEngine/ElunaCompat.cpp

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2010 - 2024 Eluna Lua Engine <https://elunaluaengine.github.io/>
+ * This program is free software licensed under GPL version 3
+ * Please see the included DOCS/LICENSE.md for more information
+ */
+
+#include "ElunaCompat.h"
+
+#if LUA_VERSION_NUM == 501
+const char* luaL_tolstring(lua_State* L, int idx, size_t* len) {
+    if (!luaL_callmeta(L, idx, "__tostring")) {
+        int t = lua_type(L, idx), tt = 0;
+        char const* name = NULL;
+        switch (t) {
+        case LUA_TNIL:
+            lua_pushliteral(L, "nil");
+            break;
+        case LUA_TSTRING:
+        case LUA_TNUMBER:
+            lua_pushvalue(L, idx);
+            break;
+        case LUA_TBOOLEAN:
+            if (lua_toboolean(L, idx))
+                lua_pushliteral(L, "true");
+            else
+                lua_pushliteral(L, "false");
+            break;
+        default:
+            tt = luaL_getmetafield(L, idx, "__name");
+            name = (tt == LUA_TSTRING) ? lua_tostring(L, -1) : lua_typename(L, t);
+            lua_pushfstring(L, "%s: %p", name, lua_topointer(L, idx));
+            if (tt != LUA_TNIL)
+                lua_replace(L, -2);
+            break;
+        }
+    }
+    else {
+        if (!lua_isstring(L, -1))
+            luaL_error(L, "'__tostring' must return a string");
+    }
+    return lua_tolstring(L, -1, len);
+}
+
+int luaL_getsubtable(lua_State* L, int i, const char* name) {
+    int abs_i = lua_absindex(L, i);
+    luaL_checkstack(L, 3, "not enough stack slots");
+    lua_pushstring(L, name);
+    lua_gettable(L, abs_i);
+    if (lua_istable(L, -1))
+        return 1;
+    lua_pop(L, 1);
+    lua_newtable(L);
+    lua_pushstring(L, name);
+    lua_pushvalue(L, -2);
+    lua_settable(L, abs_i);
+    return 0;
+}
+
+int lua_absindex(lua_State* L, int i) {
+    if (i < 0 && i > LUA_REGISTRYINDEX)
+        i += lua_gettop(L) + 1;
+    return i;
+}
+
+#if !defined LUAJIT_VERSION
+void* luaL_testudata(lua_State* L, int index, const char* tname) {
+    void* ud = lua_touserdata(L, index);
+    if (ud)
+    {
+        if (lua_getmetatable(L, index))
+        {
+            luaL_getmetatable(L, tname);
+            if (!lua_rawequal(L, -1, -2))
+                ud = NULL;
+            lua_pop(L, 2);
+            return ud;
+        }
+    }
+    return NULL;
+}
+
+void luaL_setmetatable(lua_State* L, const char* tname) {
+    lua_pushstring(L, tname);
+    lua_rawget(L, LUA_REGISTRYINDEX);
+    lua_setmetatable(L, -2);
+}
+#endif
+#endif

src/LuaEngine/ElunaCompat.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2010 - 2024 Eluna Lua Engine <https://elunaluaengine.github.io/>
+ * This program is free software licensed under GPL version 3
+ * Please see the included DOCS/LICENSE.md for more information
+ */
+
+#ifndef ELUNACOMPAT_H
+#define ELUNACOMPAT_H
+
+extern "C"
+{
+#include "lua.h"
+#include "lauxlib.h"
+};
+
+/* Compatibility layer for compiling with Lua 5.1 or LuaJIT */
+#if LUA_VERSION_NUM == 501
+    int luaL_getsubtable(lua_State* L, int i, const char* name);
+    const char* luaL_tolstring(lua_State* L, int idx, size_t* len);
+    int lua_absindex(lua_State* L, int i);
+    #define lua_pushglobaltable(L) \
+        lua_pushvalue((L), LUA_GLOBALSINDEX)
+    #define lua_rawlen(L, idx) \
+        lua_objlen(L, idx)
+    #define lua_pushunsigned(L, u) \
+        lua_pushinteger(L, u)
+    #define lua_load(L, buf_read, dec_buf, str, NULL) \
+        lua_load(L, buf_read, dec_buf, str)
+
+#if !defined LUAJIT_VERSION
+    void* luaL_testudata(lua_State* L, int index, const char* tname);
+    void luaL_setmetatable(lua_State* L, const char* tname);
+    #define luaL_setfuncs(L, l, n) luaL_register(L, NULL, l)
+#endif
+#endif
+
+#if LUA_VERSION_NUM > 502
+    #define lua_dump(L, writer, data) \
+        lua_dump(L, writer, data, 0)
+    #define lua_pushunsigned(L, u) \
+        lua_pushinteger(L, u)
+#endif
+#endif

src/LuaEngine/ElunaTemplate.h

@@ -14,6 +14,7 @@ extern "C"
 #include "lauxlib.h"
 };
 #include "LuaEngine.h"
+#include "ElunaCompat.h"
 #include "ElunaUtility.h"
 #include "SharedDefines.h"
 

src/LuaEngine/LuaEngine.cpp

@@ -8,6 +8,7 @@
 #include "LuaEngine.h"
 #include "BindingMap.h"
 #include "Chat.h"
+#include "ElunaCompat.h"
 #include "ElunaEventMgr.h"
 #include "ElunaIncludes.h"
 #include "ElunaTemplate.h"

src/LuaEngine/lmarshal.cpp

@@ -32,6 +32,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <cstdint>
+#include "ElunaCompat.h"
 
 extern "C" {
 #include "lua.h"