from_chars is a bit broken

[KaruroChori]

Somehow different compilers and libc++ versions are actually quite different. What works on native gcc is not 100% identical to what works when cross-compiling for wasm for example. And there are differences between my machine and the CI worker for some reason.
It is failing the latest release, so no good. I might have to report this upstream.

Investigate and fix in a more robust way.

[KaruroChori]

https://www.reddit.com/r/cpp_questions/comments/zg6qlt/from_chars_and_floatingpoint_issue/
It cannot be true... can it be?
How is it possible that the float overload which have been in the standard since 2017 has yet to see an implementation under clang :/.
Honestly, I don't even know what to say.

https://github.com/iboB/mscharconv is an alternative implementation which should work... but come on.

[KaruroChori]

I got some replies in here

Basically, just waiting will sort itself out. clang20 already supports the missing features; it is just a matter of updating the toolchain locally and in CI. However, what zig uses is not something I have control over... so a temporary workaround might be needed.

[KaruroChori]

Completed by adding a preprocessor if/else to expose either the std or the fast_float version based on which compiler is used.