GTK4 replacement for mp3x: asking for feedback on integration direction

Hello,

As mentioned previously, I have been looking into replacing the GTK 1.2 interface of mp3x with a GTK4-based interface.

Following your suggestion to move toward a modern cross-platform toolkit, I have been working on a GTK4 implementation. Before preparing patches, I would like to get your feedback on how such a change would best be integrated into the project.

The LAME style guide notes that changes affecting many functions should be discussed with the maintainer first. Since this touches the frontend, build system, and platform dependencies, I thought it would be better to continue the discussion on the development list rather than make assumptions.

Nothing is being submitted at this point. I am only looking for feedback on direction and preferred integration.

For context, the current implementation is working on three platforms:

Debian Linux
macOS
Windows 11
The GTK4 frontend currently builds using the autotools build system with --enable-mp3x and runs using the existing mp3xcommand-line interface on all three platforms. The Windows build was tested using MSYS2/UCRT64. I have not modified the Visual Studio/MSVC build files yet, as I wanted feedback on the preferred Windows integration approach before doing so.

The implementation keeps the existing mp3x functionality while replacing the GTK 1.2 frontend with a GTK4 frontend. The existing GTK 1.2 sources have not been removed.

I would appreciate feedback on whether this approach fits the project's direction and how you would prefer the changes to be prepared for review.

Yours,

Maya