Add missing cstdint include

[alt-graph]

This is a bugfix for the missing include of a standard library header as discovered by MSK's Jenkins build. Please review this with priority (but also note that another pull request is still in the queue). :)

[why]
On the openSUSE Tumbleweed Linux distro, compilation of to_number.h fails because of a missing declaration of uint64_t.

[how]
Include cstdint. Also, use the fully namespace-qualified form std::uint64_t as mandated by the standard.

[soerengrunewald]

Maybe we should extend our CI with a more recent distro (e.g Ubuntu 22.04, AlmaLinux9, ArchLinux).

[ohensler]

Looks good to me

[alt-graph]

Maybe we should extend our CI with a more recent distro (e.g Ubuntu 22.04, AlmaLinux9, ArchLinux).

Our Linux tests on Github are already using "Ubuntu-latest", which AFAIK currently translates to 22.04...

[Finii]

Maybe we should extend our CI with a more recent distro (e.g Ubuntu 22.04, AlmaLinux9, ArchLinux).

Well, we do run on 22.04, no?
https://github.com/actions/runner-images
We specify ubuntu-latest which is indeed not always quite up to date and usually there is a more recent release available by specifying specifically, but not at the moment.

Using anything not 'windows', 'mac-os', 'ubuntu' needs more work, though ;-)

What I did notice that we do not build on Windows; I believe we did that on Gitlab on 'my personal gitlab runner', but obviously that has not been 'ported'. I believe Lars did set up the CI here?

[Finii]

Previously we had windows, see here, running on my 'mini desktop on window sill of old office' 😬

For some reason I can not access the runner definitions anymore for GUL on gitlab? 🤔

Ah, I have not been logged in :-D

Here it is