[C++20] Enable C++20 + Fixes + FMT 9.1 (#2664)

* [CPP] Enable and build compliance with cpp20

* Windows build fix

* bump fmt version

* Updated fmt to 9.1, updated cmake minimum and verified preprocessor stuff works.

* Missing :

* Fix warning: top-level comma expression in array subscript is deprecated

* Fix warning: top-level comma expression in array subscript is deprecated

Co-authored-by: KimLS <KimLS@peqtgc.com>

libs/luabind/CMakeLists.txt

@@ -1,4 +1,4 @@
-CMAKE_MINIMUM_REQUIRED(VERSION 3.2)
+CMAKE_MINIMUM_REQUIRED(VERSION 3.12)
 
 SET(lb_sources
     src/class.cpp

libs/luabind/src/class_info.cpp

@@ -33,7 +33,7 @@ namespace luabind
 	LUABIND_API class_info get_class_info(argument const& o)
 	{
 		lua_State* L = o.interpreter();
-	
+
 		o.push(L);
         detail::object_rep* obj = detail::get_instance(L, -1);
 
@@ -106,15 +106,15 @@ namespace luabind
 	LUABIND_API void bind_class_info(lua_State* L)
 	{
 		module(L)
-		[
+		[(
 			class_<class_info>("class_info_data")
 				.def_readonly("name", &class_info::name)
 				.def_readonly("methods", &class_info::methods)
 				.def_readonly("attributes", &class_info::attributes),
-		
+
             def("class_info", &get_class_info),
             def("class_names", &get_class_names)
-		];
+		)];
 	}
 }