build(lua): adds options to compile Lua as C++

Introduces an option to compile the Lua source files as C++ instead of C.

For CMake: /D_LUA_COMPILE_AS_CPP
For xmake: --lua_compile_as_cpp=true

This allows users to choose between C and C++ compilation.

The change also includes necessary preprocessor definitions and header adjustments to handle the different compilation modes correctly.

Author: narknon

deps/first/LuaRaw/CMakeLists.txt

@@ -4,6 +4,7 @@ set(TARGET LuaRaw)
 project(${TARGET})
 
 option(UE4SS_${TARGET}_BUILD_SHARED "Build as a shared lib" OFF)
+option(LUA_COMPILE_AS_CPP "Compile Lua as C++ instead of C" OFF)
 
 set(${TARGET}_Sources
         "${CMAKE_CURRENT_SOURCE_DIR}/src/lapi.c"
@@ -45,8 +46,12 @@ set(${TARGET}_Sources
 
 # This makes the .c files be compiled with the C++ compiler
 # This causes __cplusplus to be defined which is what Lua uses to determine whether it's compiled as C or C++
-# TODO: Decide if we want to compile Lua as C++ rather than C
-# set_source_files_properties(${${TARGET}_Sources} PROPERTIES LANGUAGE CXX)
+if(LUA_COMPILE_AS_CPP)
+    message("Compiling Lua as C++")
+    set_source_files_properties(${${TARGET}_Sources} PROPERTIES LANGUAGE CXX)
+else()
+    message("Compiling Lua as C")
+endif()
 
 string(REGEX REPLACE "(.)([A-Z])" "\\1_\\2" MODULE_NAME ${TARGET})
 string(TOUPPER ${MODULE_NAME} MODULE_NAME)
@@ -64,10 +69,13 @@ target_compile_features(${TARGET} PUBLIC cxx_std_23)
 
 target_include_directories(${TARGET} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 
-target_compile_definitions(${TARGET} PRIVATE
+target_compile_definitions(${TARGET} 
+    PRIVATE
         RC_${MODULE_NAME}_EXPORTS
+    PUBLIC
         $<$<NOT:$<BOOL:${UE4SS_${TARGET}_BUILD_SHARED}>>:
-            RC_${MODULE_NAME}_BUILD_STATIC>)
+            RC_${MODULE_NAME}_BUILD_STATIC>
+        $<$<BOOL:${LUA_COMPILE_AS_CPP}>:LUA_COMPILED_AS_CPP>)
 
 # Make headers visible in the IDE
 # Uses make_headers_visible() from cmake/modules/IDEVisibility.cmake
@@ -76,5 +84,5 @@ make_headers_visible(${TARGET} "${CMAKE_CURRENT_SOURCE_DIR}/include")
 if (${CMAKE_CXX_COMPILER_ID} STREQUAL MSVC)
     target_compile_options(${TARGET} PRIVATE /W0)
 elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL Clang)
-    target_compile_options(${TARGET} PRIVATE -xc++;-Wno-deprecated-enum-enum-conversion)
+    target_compile_options(${TARGET} PRIVATE -Wno-deprecated-enum-enum-conversion)
 endif ()

deps/first/LuaRaw/include/lua.hpp

@@ -2,9 +2,14 @@
 // Lua header files for C++
 // <<extern "C">> not supplied automatically because Lua also compiles as C++
 
-
+// When Lua is compiled as C, we need extern "C" wrappers
+// When Lua is compiled as C++, we don't want them
+#ifndef LUA_COMPILED_AS_CPP
 extern "C" {
-#include "lauxlib.h"
-#include "lua.h"
-#include "lualib.h"
+#endif
+    #include "lua.h"
+    #include "lualib.h"
+    #include "lauxlib.h"
+#ifndef LUA_COMPILED_AS_CPP
 }
+#endif

deps/first/LuaRaw/xmake.lua

@@ -1,3 +1,9 @@
+option("lua_compile_as_cpp")
+    set_default(false)
+    set_showmenu(true)
+    set_description("Compile Lua source files as C++ instead of C")
+    set_category("Lua Options")
+
 local projectName = "LuaRaw"
 
 target(projectName)
@@ -7,8 +13,9 @@ target(projectName)
     add_rules("ue4ss.dependency")
     add_includedirs("include", { public = true })
     add_headerfiles("include/**.hpp")
+    add_options("lua_compile_as_cpp")
 
-    add_files(
+    local lua_sources = {
         "src/lapi.c", "src/lauxlib.c", "src/lbaselib.c", "src/lcode.c",
         "src/lcorolib.c", "src/lctype.c", "src/ldblib.c", "src/ldebug.c",
         "src/ldo.c", "src/ldump.c", "src/lfunc.c", "src/lgc.c",
@@ -18,7 +25,18 @@ target(projectName)
         "src/lstrlib.c", "src/ltable.c", "src/ltablib.c", "src/ltm.c",
         "src/luauser.c", "src/lundump.c", "src/lutf8lib.c", "src/lvm.c",
         "src/lzio.c"
-    )
+    }
 
+    local compile_as_cpp = get_config("lua_compile_as_cpp")
+    if compile_as_cpp == nil then compile_as_cpp = false end
+    
+    if compile_as_cpp then
+        add_defines("LUA_COMPILED_AS_CPP", { public = true })
+        -- Force compilation as C++
+        add_files(lua_sources, {sourcekind = "cxx"})
+    else
+        -- Compile as C
+        add_files(lua_sources)
+    end