Fixes XCode Compiler C++ Version/Dialect Output (#2397)

Author: nickclark2016

modules/xcode/tests/test_xcode_project.lua

@@ -3715,7 +3715,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ARCHS = "$(NATIVE_ARCH_ACTUAL)";
-				CLANG_CXX_LANGUAGE_STANDARD = "c++1z";
+				CLANG_CXX_LANGUAGE_STANDARD = "c++17";
 				CONFIGURATION_BUILD_DIR = "$(SYMROOT)";
 				CONFIGURATION_TEMP_DIR = "$(OBJROOT)";
 				GCC_OPTIMIZATION_LEVEL = 0;
@@ -3767,7 +3767,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ARCHS = "$(NATIVE_ARCH_ACTUAL)";
-				CLANG_CXX_LANGUAGE_STANDARD = "c++2a";
+				CLANG_CXX_LANGUAGE_STANDARD = "c++20";
 				CONFIGURATION_BUILD_DIR = "$(SYMROOT)";
 				CONFIGURATION_TEMP_DIR = "$(OBJROOT)";
 				GCC_OPTIMIZATION_LEVEL = 0;
@@ -4001,7 +4001,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ARCHS = "$(NATIVE_ARCH_ACTUAL)";
-				CLANG_CXX_LANGUAGE_STANDARD = "gnu++1z";
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++17";
 				CONFIGURATION_BUILD_DIR = "$(SYMROOT)";
 				CONFIGURATION_TEMP_DIR = "$(OBJROOT)";
 				GCC_OPTIMIZATION_LEVEL = 0;
@@ -4053,7 +4053,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ARCHS = "$(NATIVE_ARCH_ACTUAL)";
-				CLANG_CXX_LANGUAGE_STANDARD = "gnu++2a";
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++20";
 				CONFIGURATION_BUILD_DIR = "$(SYMROOT)";
 				CONFIGURATION_TEMP_DIR = "$(OBJROOT)";
 				GCC_OPTIMIZATION_LEVEL = 0;

modules/xcode/xcode_common.lua

@@ -1397,9 +1397,9 @@
 		["C++1y"] = "c++14",
 		["C++14"] = "c++14",
 		["C++1z"] = "c++1z",
-		["C++17"] = "c++1z",
+		["C++17"] = "c++17",
 		["C++2a"] = "c++2a",
-		["C++20"] = "c++2a",
+		["C++20"] = "c++20",
 		["C++2b"] = "c++2b",
 		["C++23"] = "c++23",
 		["gnu++98"] = "gnu++98",
@@ -1408,9 +1408,9 @@
 		["gnu++1y"] = "gnu++14",
 		["gnu++14"] = "gnu++14",
 		["gnu++1z"] = "gnu++1z",
-		["gnu++17"] = "gnu++1z",
+		["gnu++17"] = "gnu++17",
 		["gnu++2a"] = "gnu++2a",
-		["gnu++20"] = "gnu++2a",
+		["gnu++20"] = "gnu++20",
 		["gnu++2b"] = "gnu++2b",
 		["gnu++23"] = "gnu++23",
 	}