Rename float=64 SCons option to precision=double

[Calinou]

This avoids confusion with the old bits=64 option and building for 64-bit CPUs in general.

See #66178 (comment) and #67308.

[aaronfranke]

Sure, either way works for me.

[clayjohn]

To me precision=64 implies that all int and float types will use 64 bits of precision. As far as I know, it will only apply to floats so the name precision is misleading

[akien-mga]

To me precision=64 implies that all int and float types will use 64 bits of precision. As far as I know, it will only apply to floats so the name precision is misleading

Here it would be precision=single|double and those terms are usually only used for floating point precision so I think it might be OK.

Alternatively, we could use real_t=single|double or real=single|double to match how it's called internally.

[fire]

I have no opinion. More concerned about the feature being stabilized and gone through testing.

[DeeJayLSP]

Why not float=single|double? It is more obvious and straight to the point.

[akien-mga]

Suggested change

	opts.Add(EnumVariable("precision", "Set the floating-point precision level", "single", ("single", "double")))
	opts.Add(EnumVariable("precision", "Set the floating-point precision level (`real_t`)", "single", ("single", "double")))

[akien-mga]

Approved in PR review meeting. We agreed that precision=single|double makes the most sense.

It's still not perfect because it's not the floating point precision for everything. Many things are already double and this can't be configured (e.g. Variant::FLOAT is double, floats in GDScript are always 64-bit - but floats within Vector/Matrix types are using real_t and affected by this setting).

That's something for the documentation to cover however, for the setting it's good enough.

[akien-mga]

CI needs to be updated:

Run ./bin/godot.linuxbsd.editor.dev.double.x86_64.san --version
/home/runner/work/_temp/007c26df-e409-44c2-9691-821a6ea78f70.sh: line 1: ./bin/godot.linuxbsd.editor.dev.double.x86_64.san: No such file or directory

[akien-mga]

Ping.

Note that the docs will need to be updated too after #68579 is merged.

[akien-mga]

Thanks!