Cleanup: use std::optional instead of custom implementation.

src/3rdparty/optional/LICENSE_1_0.txt

@@ -1,23 +0,0 @@
-Boost Software License - Version 1.0 - August 17th, 2003
-
-Permission is hereby granted, free of charge, to any person or organization
-obtaining a copy of the software and accompanying documentation covered by
-this license (the "Software") to use, reproduce, display, distribute,
-execute, and transmit the Software, and to prepare derivative works of the
-Software, and to permit third-parties to whom the Software is furnished to
-do so, all subject to the following:
-
-The copyright notices in the Software and this entire statement, including
-the above license grant, this restriction and the following disclaimer,
-must be included in all copies of the Software, in whole or in part, and
-all derivative works of the Software, unless such copies or derivative
-works are solely in the form of machine-executable object code generated by
-a source language processor.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
-SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
-FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
-ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.

src/3rdparty/optional/ottd_optional.h

@@ -1,33 +0,0 @@
-/*
- * This file is part of OpenTTD.
- * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
- * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
- */
-
-/** @file ottd_optional.h Header to select between native. */
-
-#ifndef OTTD_OPTIONAL_H
-#define OTTD_OPTIONAL_H
-
-#if defined(__has_include)
-#	if __has_include(<version>)
-#		include <version>
-#	endif
-#endif
-
-#if (__cplusplus >= 201703L) || (defined(__cpp_lib_optional) && __cpp_lib_optional >= 201606L)
-
-/* Native std::optional. */
-#include <optional>
-namespace opt = std;
-
-#else
-
-/* No std::optional, use local copy instead. */
-#include "optional.hpp"
-namespace opt = std::experimental;
-
-#endif
-
-#endif /* OTTD_OPTIONAL_H */

src/ini_type.h

@@ -12,7 +12,7 @@
 
 #include "fileio_type.h"
 #include <string>
-#include "3rdparty/optional/ottd_optional.h"
+#include <optional>
 
 /** Types of groups */
 enum IniGroupType {
@@ -25,7 +25,7 @@ enum IniGroupType {
 struct IniItem {
 	IniItem *next;                    ///< The next item in this group
 	std::string name;                 ///< The name of this item
-	opt::optional<std::string> value; ///< The value of this item
+	std::optional<std::string> value; ///< The value of this item
 	std::string comment;              ///< The comment associated with this item
 
 	IniItem(struct IniGroup *parent, const std::string &name);