Workaround missing std::bit_cast on some compilers

src/3rdparty/squirrel/squirrel/sqcompiler.cpp

@@ -15,6 +15,8 @@
 #include "sqvm.h"
 #include "sqtable.h"
 
+#include "../../../core/bit_cast.hpp"
+
 #include "../../../string_func.h"
 
 #include "../../../safeguards.h"

src/3rdparty/squirrel/squirrel/sqfuncstate.cpp

@@ -12,6 +12,8 @@
 #include "sqopcodes.h"
 #include "sqfuncstate.h"
 
+#include "../../../core/bit_cast.hpp"
+
 #include "../../../safeguards.h"
 
 #ifdef _DEBUG_DUMP

src/3rdparty/squirrel/squirrel/sqvm.cpp

@@ -17,6 +17,8 @@
 #include "sqarray.h"
 #include "sqclass.h"
 
+#include "../../../core/bit_cast.hpp"
+
 #include "../../../string_func.h"
 
 #include "../../../safeguards.h"

src/core/CMakeLists.txt

@@ -3,6 +3,7 @@ add_files(
     alloc_func.hpp
     alloc_type.hpp
     backup_type.hpp
+    bit_cast.hpp
     bitmath_func.hpp
     checksum_func.hpp
     container_func.hpp

src/core/bit_cast.hpp

@@ -0,0 +1,35 @@
+/*
+ * 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 bit_cast.hpp std::bit_cast fallback */
+
+#ifndef BIT_CAST_HPP
+#define BIT_CAST_HPP
+
+#ifdef __cpp_lib_bit_cast
+
+#include <bit>
+
+#else
+
+#include <type_traits>
+
+namespace std {
+template <typename To, typename From>
+constexpr To bit_cast(const From& from) noexcept
+{
+	static_assert(std::is_trivially_constructible_v<To>);
+
+	To to;
+	memcpy(&to, &from, sizeof(To));
+	return to;
+}
+}
+
+#endif
+
+#endif /* BIT_CAST_HPP */