[clang] [llvm] [LLVM] Add GNU make jobserver support (PR #145131)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-lld-multistage-test` running on `ppc64le-lld-multistage-test` while building `clang,llvm` at step 6 "build-stage1-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/16481

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (build-stage1-unified-tree) failure: build (failure) (timed out)
...
2361.236 [6265/11/444] Linking CXX executable unittests/DebugInfo/CodeView/DebugInfoCodeViewTests
2363.225 [6265/10/445] Linking CXX executable unittests/Support/LSP/LLVMSupportLSPTests
2366.198 [6265/9/446] Linking CXX executable unittests/LineEditor/LineEditorTests
2367.708 [6265/8/447] Linking CXX executable unittests/Testing/ADT/TestingADTTests
2373.906 [6265/7/448] Linking CXX executable unittests/FileCheck/FileCheckTests
2377.904 [6265/6/449] Linking CXX executable unittests/Demangle/DemangleTests
2385.997 [6265/5/450] Linking CXX executable unittests/CAS/CASTests
2399.154 [6265/4/451] Linking CXX executable bin/llvm-min-tblgen
2402.412 [6265/3/452] Linking CXX executable bin/clang-tblgen
2492.475 [6265/2/453] Linking CXX executable unittests/Support/DynamicLibrary/DynamicLibraryTests
command timed out: 1200 seconds without output running [b'ninja'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=3693.295799

```

</details>

https://github.com/llvm/llvm-project/pull/145131