Add @nogc UDA, fix some small issues, xmake changes

-add @nogc to some functions where it was missing
-fix compilation issue in mallocator
-fix Meson build
-some work on xmake build

dub.json

@@ -7,9 +7,9 @@
 	"description": "Dynamic Entity Component System",
 	"copyright": "Copyright © 2018-2023, Michał Masiukiewicz, Dawid Masiukiewicz",
 	"license": "BSD 3-clause",
-	"sourcePaths" : ["source\/"],
+	"sourcePaths" : ["source/"],
 	"excludedSourceFiles":[
-		"source\/ecs\/traits.d"
+		"source/ecs/traits.d"
 	],
 	"configurations" : [
 		{
@@ -21,7 +21,7 @@
 			"sourceFiles" : ["tests/tests.d"],
 			"targetType" : "executable",
 			"excludedSourceFiles":[
-				"source\/win_dll.d"
+				"source/win_dll.d"
 			]
 		},
 		{
@@ -45,7 +45,7 @@
 			"sourcePaths": ["source/","tests/"],
 			"mainSourceFile":"tests/runner.d",
 			"excludedSourceFiles":[
-				"source\/win_dll.d",
+				"source/win_dll.d",
 				"tests/tests.d"
 			],
 			"dflags": [
@@ -58,7 +58,7 @@
 			"sourcePaths": ["source/","tests/"],
 			"mainSourceFile":"tests/runner.d",
 			"excludedSourceFiles":[
-				"source\/win_dll.d",
+				"source/win_dll.d",
 				"tests/tests.d"
 			],
 			"dflags": [
@@ -70,7 +70,7 @@
 			"name" : "library-betterC",
 			"targetType" : "library",
 			"excludedSourceFiles":[
-				"source\/win_dll.d"
+				"source/win_dll.d"
 			],
 			"dflags": [
 				"-betterC",
@@ -101,7 +101,7 @@
 			"targetType" : "executable",
 			"sourceFiles" : ["tests/tests.d"],
 			"excludedSourceFiles":[
-				"source\/win_dll.d"
+				"source/win_dll.d"
 			],
 			"dflags": [
 				"-betterC"
@@ -125,7 +125,7 @@
 			"sourcePaths": ["source/","tests/"],
 			"mainSourceFile":"tests/runner.d",
 			"excludedSourceFiles":[
-				"source\/win_dll.d",
+				"source/win_dll.d",
 				"tests/tests.d"
 			]
 		}