[clang] [llvm] Add missing clang to the monolithic pre-merge build (PR #85354)

[Mehdi Amini via cfe-commits]

https://github.com/joker-eph created https://github.com/llvm/llvm-project/pull/85354

Clang has a custom separate pipeline integrated with libc++ that only runs in release mode. It means that changes which touches only clang won't run the clang tests in the configuration used by LLVM premerge and will break it unknowingly.

>From d4286b64b9e4eb7743edccbe3f1a3c117a8d0fc0 Mon Sep 17 00:00:00 2001
From: Mehdi Amini <joker.eph at gmail.com>
Date: Thu, 14 Mar 2024 19:49:29 -0700
Subject: [PATCH] Add missing clang to the monolithic pre-merge build

Clang has a custom separate pipeline integrated with libc++
that only runs in release mode. It means that changes which touches
only clang won't run the clang tests in the configuration used by
LLVM premerge and will break it unknowingly.
---
 .ci/generate-buildkite-pipeline-premerge | 2 +-
 clang/empty_trigger                      | 0
 2 files changed, 1 insertion(+), 1 deletion(-)
 create mode 100644 clang/empty_trigger

diff --git a/.ci/generate-buildkite-pipeline-premerge b/.ci/generate-buildkite-pipeline-premerge
index 4ebf304e23d587..b0a995dc8d7df4 100755
--- a/.ci/generate-buildkite-pipeline-premerge
+++ b/.ci/generate-buildkite-pipeline-premerge
@@ -224,7 +224,7 @@ fi
 # needs while letting them run on the infrastructure provided by LLVM.
 
 # Figure out which projects need to be built on each platform
-all_projects="bolt clang-tools-extra compiler-rt cross-project-tests flang libc libclc lld lldb llvm mlir openmp polly pstl"
+all_projects="bolt clang clang-tools-extra compiler-rt cross-project-tests flang libc libclc lld lldb llvm mlir openmp polly pstl"
 modified_projects="$(keep-modified-projects ${all_projects})"
 
 linux_projects_to_test=$(exclude-linux $(compute-projects-to-test ${modified_projects}))
diff --git a/clang/empty_trigger b/clang/empty_trigger
new file mode 100644
index 00000000000000..e69de29bb2d1d6