Add MinGW-w64 support

[eawd123wadd4354as243df]

Adds support for building with MinGW-w64.
This is WIP, as linking still fails.

Open TODOs:

• Fix linking issues with missing D3D in imgui
• Blocked: Check if this works on windows, and if MSVC still works.
• Document build requirements:
  • Powershell core installed on system (on linux, I think on windows it is installed automatically)
  • MinGW-w64 (obv)

[eawd123wadd4354as243df]

I chose MinGW as it makes it easy to link windows headers, but once it builds I will attempt to migrate to clang as well.
Do we want to keep supporting MSVC / the VS build system, AND clang AND MinGW?

[fairangelica]

I personally am certainly in favor of dropping MSVC and the VS Build System, as both Clang and CMake are alternatives that are natively supported in Visual Studio ("C++ Clang Tools for Windows" and "C++ CMake for Windows" exist as components one can install easily in the VS Installer)

I would love MingGW support, but we would first need to move to CMake and Clang, as the VS Build System gets awkward when trying to integrate that into the XML config file.

But in the end it is in the discretion of @BreakingBread0 to veto this ^^

[fairangelica]

I chose MinGW as it makes it easy to link windows headers, but once it builds I will attempt to migrate to clang as well.

also, might I interest you in checking out MinGW-LLVM? It might be nicer to move to that as I already worked a bit on the possible Clang migration ^^

[BreakingBread0]

Oh yeah im definitely in favour of switching from MSVC in the long term. That compiler is.... interesting to say the least and I had to fight it a few times with this small project already hahaha

Did you get further with compiling this project with clang/mingw? I can adapt this to @Hazno-dev 's branch

[Twig6943]

Yo, bumping this.

I can try doing something like this if you're interested @BreakingBread0