Replace header guards of type `#ifndef` with a `#pragma once`

[kunaltyagi]

Replace #ifndef header guard with a #pragma once

_Originally posted by @kunaltyagi in https://github.com/render_node/MDIzOlB1bGxSZXF1ZXN0UmV2aWV3VGhyZWFkMjQ0Nzg4MDI0OnYy/pull_request_review_threads/discussion

Maybe there's a clang-tidy flag to do this.

[0sidharth]

Can I work on this?

[stale[bot]]

Marking this as stale due to 30 days of inactivity. It will be closed in 7 days if no further activity occurs.

[mvieth]

If anyone is interested: this is still open. Here is a list of remaining header guards: header_guards.txt (I used grep with ifndef.*h, the list is probably complete but contains some false positives). I would recommend applying the changes in more than one pull request. The closed pull request above mentions some tools that may make the work easier.

[MallikharjunaTeja]

Hi @mvieth i want to work on this could you please assign me this

[mvieth]

@MallikharjunaTeja Great! Please open multiple smaller pull requests instead of one big pull request for the changes (maybe about 50-100 changed files per pull request)

[mvieth]

@MallikharjunaTeja Are you still planning to open a pull request?

[Zekrom-7780]

@mvieth I'll take up this issue