Add support for long double

[GuillaumeGomez]

Needed for rust-lang/libc#2565.

[GuillaumeGomez]

ping @JohnTitor

[JohnTitor]

Looks fine, could you also add a test case here? https://github.com/JohnTitor/ctest2/tree/master/testcrate/src

[GuillaumeGomez]

From what I can read, it's supposed to compare the rust equivalent, however long double has no equivalent in Rust. So: how can I add a test for a type which doesn't exist in rust?

[JohnTitor]

I wanted to ensure that it works fine by replicating code from the above libc PR, doesn't it make much sense? If not, I'm fine to merge as-is.

[GuillaumeGomez]

I can give it a try at least.

[GuillaumeGomez]

Let's see how it goes now. :3

[GuillaumeGomez]

@JohnTitor Does the test looks ok to you?

[JohnTitor]

Yeah, thanks a lot!

[GuillaumeGomez]

Thanks for the release! :)