[NFC] update llvm version to 20.1 and branch to llvm_release_200 (#564)

[NFC] update llvm version to 19.1 and branch to llvm_release_190 (#550)

[Backport] Do not apply patches if sub non-git repo is located in a g…

…it repo. (#543)

[Backport] Do not apply patches if repo is a not a git repo.
#539
[Backport] Do not apply patches if sub non-git repo is located in a git
repo. #545
Also add an option to control patch apply which is default on. Pass
-DAPPLY_PATCHES=OFF will skip patch apply process.
Update LLVM_BASE_REVISION.

[Backport] Do not apply patches if sub non-git repo is located in a g…

…it repo. (#542)

[Backport] Do not apply patches if repo is a not a git repo.
#539
[Backport] Do not apply patches if sub non-git repo is located in a git
repo. #545
Also add an option to control patch apply which is default on. Pass
-DAPPLY_PATCHES=OFF will skip patch apply process.
Update LLVM_BASE_REVISION.

[Backport] Do not apply patches if sub non-git repo is located in a g…

…it repo. (#541)

[Backport] Do not apply patches if repo is a not a git repo.
#539
[Backport] Do not apply patches if sub non-git repo is located in a git
repo. #545
Also add an option to control patch apply which is default on. Pass
-DAPPLY_PATCHES=OFF will skip patch apply process.
Update LLVM_BASE_REVISION.

[Backport] Do not apply patches if sub non-git repo is located in a g…

…it repo. (#540)

[Backport] Do not apply patches if repo is a not a git repo.
#539
[Backport] Do not apply patches if sub non-git repo is located in a git
repo. #545
Also add an option to control patch apply which is default on. Pass
-DAPPLY_PATCHES=OFF will skip patch apply process.

Do not apply patches if sub non-git repo is located in a git repo. (#545

)

follow up #539.
Also add an option to control patch apply which is default on. Pass
-DAPPLY_PATCHES=OFF will skip patch apply process.

llvm minor version is required: 18.1

Add OpenCL clang extension for bit fields (#505)

It's a manual backport of change:

llvm/llvm-project@237c692

Revert "add 'Visibility' field to Option (#474)"

This reverts commit 45180f6.