Build OBS and OBS Shaderfilter with open source toolchain on Windows

[skeletonbow]

It is my goal to build OBS Studio and OBS plugins from source code on the Windows operating system using an open source toolchain such as Clang/MinGW or similar, in order to avoid reliance on Microsoft's proprietary toolchain.

The OBS Project official Build Instructions For Windows currently provides 2 supported methods for building OBS Studio for Windows, both of which use and require Microsoft's free proprietary Visual Studio 2019 Community Edition in order to build the software at the time of this writing. While the Community Edition of Microsoft's software is currently available at no cost it itself is not open source, and this older version of Visual Studio requires authenticating with the Microsoft website using a Microsoft login account in order to gain access to download which is undesirable.

A minor amount of research has suggested to me that it may be possible to build OBS Studio and plugins for it on Windows by using Clang with MinGW, however it will require a deeper investigation to figure out how to do this as it does not appear to be documented anywhere and is most likely not an officially supported way of building OBS by the project on Windows.

Nonetheless, I will need to find a solution to building OBS Studio and plugins on Windows that do not require Microsoft's proprietary tools in order to proceed, so this should be a fun project to take on.

Requirements:

• Build OBS Studio, and OBS Shaderfilter from source using only open source tools on the Windows operating system.
• The built plugin needs to be compatible with and loadable with the official OBS Studio binary release distributed by the OBS Project for Windows.

Additional notes:

• The use of open source or proprietary tools which are available free of cost, and do not require a user account login or present any other limitations or restrictions is potentially acceptable depending on the circumstances.

Rationale:
I want to develop and contribute to an open source project's ecosystem without requiring permission/approval from Microsoft to do so, in the spirit of fundamental open source principles.

[skeletonbow]

H4ndy suggests OBS deps are cross-compiled in github actions already, so that might be a good starting point: