Fix Pinned Build on Ubuntu 22.04

[kj4ezj]

From issue 735, this reverts pull request 799 (Search for LLVM versions 7-11, prefering latest version) to fix the pinned build on Ubuntu 22.04. There are no other changes in this PR besides the revert.

Pull request 799 introduced code that attempts to automagically find the correct version of LLVM for the Leap build on systems that have multiple versions of LLVM installed and available. This code only runs when cmake is version 3.19 or newer. Ubuntu 22.04 ships with CMake version 3.22.1, following the new code path, whereas Ubuntu 20.04 ships with version 3.16.3 that does not follow the new code path. This explains why the pinned build only fails on Ubuntu 22.04.

I have verified the Ubuntu 22.04 pinned build works on this branch.

Credit to @spoonincode for identifying the cause of the bug.

See Also

1. Pull Request 833 - Fix Pinned Build on Ubuntu 22.04
   • Reverts pull request 799
2. Pull Request 812 - Pinned Build Script Linter Changes
3. Pull Request 835 - Change ASCII Art Banner in Build Script
4. Pull Request 832 - Roll install_deps.sh into pinned_build.sh
5. Pull Request 847 - Restore libcurl4-openssl-dev
6. Pull Request 849 - Fix README.md Formatting
7. Pull Request 870 - Pinned Build Script Backport Omnibus
8. Pull Request 857 - Simplify Pinned Build Scripts
9. Pull Request 811 - Pinned Build Script Changes

[spoonincode]

I'm fine with reverting this until a fix is decided on, so we can get the builds operational again asap

maybe we just go with #834

[ScottBailey]

If #834 fixes the defect, this should be abandoned. #799 does not fail for my non-pinned builds.

[ScottBailey]

Evaluate #834 and abandon this if its a solution.

[spoonincode]

#834 works but isn't production ready due to it not working with existing dep directories (ugh.. build scripts). #799 is basically causing a release blocker for a nice-to-have.. so I guess I'm back to my "revert it until someone comes up with a shipable fix" approval.

[kj4ezj]

Evaluate #834 and abandon this if its a solution.

The base branch is broken and the 4.0 release is blocked. The correct thing to do is to revert the breaking change.

If someone wants to try to re-implement the feature we were attempting to introduce, anyone is welcome to post up another PR. The PR you suggested is a draft, it is not ready for peer review and we do not even know if it would fix the problem if it were. Reverting breaking changes is always the right thing to do because we want the base branch to be in a working state at any given point in time.

[spoonincode]

fwiw I changed #834 to a draft after Scott made his comment -- after I realized it didn't work in all cases because of how the script works. It does otherwise fix the issue with a fresh depdir