fix(README) : Prepare Prerequisites on Arch Linux

[xiaguan]

After I install arch linux and prepare according to the prompt of README.MD. When I excute the commands follows , error occurs.

# In the TiFlash repository root:
mkdir cmake-build-debug  # The directory name can be customized
cd cmake-build-debug

cmake .. -GNinja -DCMAKE_BUILD_TYPE=DEBUG

ninja tiflash

error(cmake/tools.cmake:87):

Cannot find ar.

After excute

sudo pacman -S llvm

No error occurs again.

What problem does this PR solve?

Issue Number: close #6800
Problem Summary: Prepare Prerequisites on Arch Linux is not enough. We should add ' llvm ' .

What is changed and how it works?

Just append ' llvm ' in prepare commands on Arch Linux in README.md

Check List

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Lloyd-Pottiger
• ywqzzy

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[sre-bot]

All committers have signed the CLA.

[ti-chi-bot]

Welcome @xiaguan!

It looks like this is your first PR to pingcap/tiflash 🎉.

I'm the bot to help you request reviewers, add labels and more, See available commands.

We want to make sure your contribution gets all the attention it needs!



Thank you, and welcome to pingcap/tiflash. 😃

[Lloyd-Pottiger]

Thanks for your contribution. But we have mention llvm in line59 - 61 🤔

[xiaguan]

I just read the 59-61 lines of readme.md. Is that the content of Ubuntu not Arch Linux ?

[xiaguan]

/run-all-tests

[Lloyd-Pottiger]

/merge

[ti-chi-bot]

@Lloyd-Pottiger: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 54956c4