Add a build profile with no disabled classes and pass it by default

[unvermuthet]

I suggested adding this file by default to hint at the fact that doing this is possible. Disabling unused classes can save a lot of time when compiling godot-cpp.

I'm not very familiar with SCons. Is localEnv a good place to set it? This way it seems to show up as the default when running scons --help.

Is the .json file extension a good idea? When exporting profiles from the editor .profile is the default. I went with .json because of language detection and syntax highlighting.

[Ivorforce]

I'd suggest the following:

Suggested change

	localEnv["build_profile"] = "build_profile.json"
	if ARGUMENTS.get("build_profile", None) is None:
	# Using small build profiles decreases compile time.
	# The file starts out empty. Edit it to benefit from decreased compile times.
	ARGUMENTS["build_profile"] = str("build_profile.json")

(further up; at least before the env is created)

ARGUMENTS.setdefault("build_profile", "build_profile.json") should also work on new SCons versions, but my local scons actually didn't support it so I'd suggest if.

The comment above can be improved with a link to a docs entry for build profiles once we have one.

[Ivorforce]

Another option would be to fail if the build_profile option is manually set because it probably shouldn't. But I don't see why I'd deny a user this configuration if it's explicitly requested.

[unvermuthet]

On my SCons version this code makes help show:

build_profile: Path to a file containing a feature build profile ( /path/to/build_profile )
    default: None
    actual: build_profile.json

[unvermuthet]

With the way it is, it show the default and can be replaced for me:

build_profile: Path to a file containing a feature build profile ( /path/to/build_profile )
    default: build_profile.json
    actual: copy.json

[Ivorforce]

Is this the case for both implementations?

The reason I'd recommend against localEnv["build_profile"] = "build_profile.json" is because it would silently ignore build_profile=some_build_profile.json arguments, overriding with the default value. This could potentially cause hard to debug problems.

[Ivorforce]

Ah... perhaps this is because godot-cpp re-extracts the parameter after it's set?
I'm not sure which is the 'SCons' way to handle this. Yours seems better integrated, I suppose, so if it works it may be a better approach.