Set proper cmake versions for different C/C++ versions

kmake/src/Exporters/CMakeExporter.ts

@@ -17,9 +17,60 @@ export class CMakeExporter extends Exporter {
 
 		this.writeFile(path.resolve(to, name, 'CMakeLists.txt'));
 
-		this.p('cmake_minimum_required(VERSION 3.10)');  // should be 3.12 to support c++20, 3.20 to support c++23 and 3.21 to support c17/c23
+		let cmakeVersion = '3.10';
+
+		switch (project.cppStd) {
+			case 'gnu++03':
+			case 'c++03':
+			case 'gnu++11':
+			case 'c++11':
+			case 'gnu++14':
+			case 'c++14':
+			case 'gnu++17':
+			case 'c++17':
+				break;
+			case 'gnu++2a':
+			case 'c++2a':
+			case 'gnu++20':
+			case 'c++20':
+				cmakeVersion = '3.12';
+				break;
+			case 'gnu++2b':
+			case 'c++2b':
+			case 'gnu++23':
+			case 'c++23':
+				cmakeVersion = '3.20';
+				break;
+			default:
+				break;
+		}
+
+		switch (project.cStd) {
+			case 'gnu9x':
+			case 'gnu99':
+			case 'c9x':
+			case 'c99':
+			case 'gnu1x':
+			case 'gnu11':
+			case 'c1x':
+			case 'c11':
+				break;
+			case 'gnu18':
+			case 'gnu17':
+			case 'c18':
+			case 'c17':
+			case 'gnu2x':
+			case 'c2x':
+				cmakeVersion = '3.21';
+				break;
+			default:
+				break;
+		}
+
+		this.p('cmake_minimum_required(VERSION ' + cmakeVersion + ')');
 
 		this.p('project(' + name + ')');
+
 		switch (project.cppStd) {
 			case 'gnu++03':
 			case 'c++03':