SCons: Convert platform get_flags to dictionary

[Repiteo]

Minor formatting update to make get_flags return a dictionary instead of a tuple array, as it's already being parsed as if it were a dictionary.

[Riteo]

Makes sense! Definitely improves readability :D

[Eoin-ONeill-Yokai]

This looks great. It certainly helps the readability of the flags section for platform code.

[akien-mga]

In general this makes a lot of sense, but I'm a bit concerned that it's compat breaking for third-party platform ports: consoles, homebrews, embedded devices, etc.

I can say from the W4 side that it's a change we're happy to carry over downstream, but I can't make that decision for all other third-parties, who may be trying to support multiple Godot minor releases for the same codebase (with a few occasionally #ifdefs checking the Godot version).

I just had a quick look and it seems possible to preserve compatibility downstream by doing a Godot version check like this:

def get_flags():
    import version

    if (version.major, version.minor) < (4, 3):
        return [
            ("arch", detect_arch()),
            ("supported", ["mono"]),
        ]
    else:
        return {
            "arch": detect_arch(),
            "supported": ["mono"],
        }

So I think it's fine for now, I'm not aware of downstream ports that would want to support multiple versions, but if some do, they can use a similar snippet to achieve that.

We should keep this in mind if we ever want to make get_flags() strongly typed to Dictionary, which may prevent such workaround. (So if you're a downstream port maintainer reading this and relying on such a workaround, please make yourself known.)

[akien-mga]

Note, one other option would be to add compat code ourselves in SConstruct, handling the get_flags() results differently based on whether it's a list or a dictionary.

We had to do that in the past when change the expected arguments of the modules' can_build, as way too many thirdparty modules broke unnecessarily. Here the risk is more theoretical, thirdparty platforms are a lot less widespread than modules, so it may not be worth the added complexity in our SConstruct. Though we could hide the complexity away in methods.py and just call a method to convert the array to a dict.

[Repiteo]

A compatibility check was easy enough to implement:

        platform_flags[x] = detect.get_flags()
        if isinstance(platform_flags[x], list):  # backwards compatibility
            platform_flags[x] = {flag[0]: flag[1] for flag in platform_flags[x]}

[akien-mga]

Looks great!

[akien-mga]

Thanks!