Fix exit code of --help and --version, and test them in CI

Corrects prior regression which caused ERROR output and exit code of 1.

(cherry picked from commit d38d76d)

main/main.cpp

@@ -497,12 +497,12 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 		if (I->get() == "-h" || I->get() == "--help" || I->get() == "/?") { // display help
 
 			show_help = true;
-			exit_code = OK;
+			exit_code = ERR_HELP; // Hack to force an early exit in `main()` with a success code.
 			goto error;
 
 		} else if (I->get() == "--version") {
 			print_line(get_full_version_string());
-			exit_code = OK;
+			exit_code = ERR_HELP; // Hack to force an early exit in `main()` with a success code.
 			goto error;
 
 		} else if (I->get() == "-v" || I->get() == "--verbose") { // verbose output

platform/android/java_godot_lib_jni.cpp

@@ -199,6 +199,7 @@ JNIEXPORT void JNICALL Java_org_godotengine_godot_GodotLib_setup(JNIEnv *env, jc
 		memfree(cmdline);
 	}
 
+	// Note: --help and --version return ERR_HELP, but this should be translated to 0 if exit codes are propagated.
 	if (err != OK) {
 		return; // should exit instead and print the error
 	}

platform/iphone/godot_iphone.mm

@@ -103,7 +103,10 @@ int iphone_main(int argc, char **argv, String data_dir, String cache_dir) {
 	printf("os created\n");
 	Error err = Main::setup(fargv[0], argc - 1, &fargv[1], false);
 	printf("setup %i\n", err);
-	if (err != OK) {
+
+	if (err == ERR_HELP) { // Returned by --help and --version, so success.
+		return 0;
+	} else if (err != OK) {
 		return 255;
 	}
 

platform/osx/godot_main_osx.mm

@@ -64,8 +64,11 @@ int main(int argc, char **argv) {
 		err = Main::setup(argv[0], argc - first_arg, &argv[first_arg]);
 	}
 
-	if (err != OK)
+	if (err == ERR_HELP) { // Returned by --help and --version, so success.
+		return 0;
+	} else if (err != OK) {
 		return 255;
+	}
 
 	if (Main::start())
 		os.run(); // it is actually the OS that decides how to run

platform/windows/godot_windows.cpp

@@ -164,6 +164,10 @@ __declspec(dllexport) int widechar_main(int argc, wchar_t **argv) {
 			delete[] argv_utf8[i];
 		}
 		delete[] argv_utf8;
+
+		if (err == ERR_HELP) { // Returned by --help and --version, so success.
+			return 0;
+		}
 		return 255;
 	}
 

platform/x11/godot_x11.cpp

@@ -48,6 +48,10 @@ int main(int argc, char *argv[]) {
 	Error err = Main::setup(argv[0], argc - 1, &argv[1]);
 	if (err != OK) {
 		free(cwd);
+
+		if (err == ERR_HELP) { // Returned by --help and --version, so success.
+			return 0;
+		}
 		return 255;
 	}