@nogc and Phobos

[bomat]

Thanks for the responses everyone, that was all very helpful and 
got me on the right track.
Especially this:

On Saturday, 11 March 2023 at 14:41:01 UTC, Steven Schveighoffer 
wrote:
> I think it is an error to mark a library which centers on 
> callbacks with always being @nogc. You can work around nothrow 
> and @safe, but not @nogc.

Turns out it was my fault. I was working off example code that 
came with d-imgui, and the original author took the (rather lazy) 
approach of wrapping the entire main loop into `nothrow @nogc:` I 
just got rid of that and only marked the callbacks accordingly.
Now I can just set status data in the callbacks, then handle it 
in the main loop.

Sorry, still kinda finding my feet here. :)