Reworked ASSERT() and Int3() macros to use SDL_assert(). SDL_assert() allows to debug break from user decision.
Major reorganizing platform-dependent code to make it platform-independent.
Message box did not display correctly when cancelling (ESC) the pilot selection menu, allowing entering the game without a valid pilot. Cancel handling now uses safer std::filesystem logic.
Hex string values from the registry containing an alpha character were parsed incorrectly. Use more standard hex parsing instead of hand-made incorrect function
When we have no config file yet, e.g. on first start of the game, or the entry for "Default_pilot" is missing in the config, the variable Default_pilot will be filled with random memory. This might later crash when we try to interpret this string as std::filesystem::path in PilotSelect() in pilot.cpp.
Under gcc-9 (e.g. used by Ubuntu 20.04), compilation fails with:
```
/usr/include/c++/9/variant: In instantiation of ‘constexpr const size_t std::variant_size_v<user_var>’:
/usr/include/c++/9/variant:1023:10: required from ‘struct std::__detail::__variant::__gen_vtable<true, void, user_var::operator++(int)::<lambda(auto:22&&)>&&, user_var&>’
/usr/include/c++/9/variant:1656:23: required from ‘constexpr decltype(auto) std::__do_visit(_Visitor&&, _Variants&& ...) [with bool __use_index = false; bool __same_return_types = true; _Visitor = user_var::operator++(int)::<lambda(auto:22&&)>; _Variants = {user_var&}]’
/usr/include/c++/9/variant:1672:29: required from ‘constexpr std::__detail::__variant::__visit_result_t<_Visitor, _Variants ...> std::visit(_Visitor&&, _Variants&& ...) [with _Visitor = user_var::operator++(int)::<lambda(auto:22&&)>; _Variants = {user_var&}; std::__detail::__variant::__visit_result_t<_Visitor, _Variants ...> = void]’
scripts/DallasFuncs.h:21:75: required from here
/usr/include/c++/9/variant:94:29: error: incomplete type ‘std::variant_size<user_var>’ used in nested name specifier
94 | inline constexpr size_t variant_size_v = variant_size<_Variant>::value;
```
Judging from the date of P2162, calling std::visit with std::variant
derivatives is only specified for C++20 and onwards. But Descent3
only asks for C++17.
Since ``class user_var`` does not have any members that need would
need to be accessed via std::visit, we can "add a hint" and
explicitly specify the base type.
Removes key_emulation and joy_emulation toggles from ddio_init_info structures, that were not used in the SDL implementation.
All input is now handled using SDL for all platforms, alternatejoy/directinput options were only relevant for Windows-specific DirectInput. 'slowkey' was an unimplemented feature.
