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

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/25464

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM-Unit :: Support/./SupportTests/9/52' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/unittests/Support/./SupportTests-LLVM-Unit-557-9-52.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=52 GTEST_SHARD_INDEX=9 /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/unittests/Support/./SupportTests
--


Note: This is test shard 10 of 52.
[==========] Running 32 tests from 32 test suites.
[----------] Global test environment set-up.
[----------] 1 test from AlignmentTest
[ RUN      ] AlignmentTest.AlignOfConstant
[       OK ] AlignmentTest.AlignOfConstant (0 ms)
[----------] 1 test from AlignmentTest (0 ms total)

[----------] 1 test from AlignNeededBuildAttr
[ RUN      ] AlignNeededBuildAttr.testBuildAttr
[       OK ] AlignNeededBuildAttr.testBuildAttr (0 ms)
[----------] 1 test from AlignNeededBuildAttr (0 ms total)

[----------] 1 test from BalancedPartitioningTest
[ RUN      ] BalancedPartitioningTest.MoveGain
[       OK ] BalancedPartitioningTest.MoveGain (0 ms)
[----------] 1 test from BalancedPartitioningTest (0 ms total)

[----------] 1 test from CheckedArithmetic
[ RUN      ] CheckedArithmetic.CheckedAddUnsigned
[       OK ] CheckedArithmetic.CheckedAddUnsigned (0 ms)
[----------] 1 test from CheckedArithmetic (0 ms total)

[----------] 1 test from CommandLineTest
[ RUN      ] CommandLineTest.ReadConfigFile
[       OK ] CommandLineTest.ReadConfigFile (0 ms)
[----------] 1 test from CommandLineTest (0 ms total)

[----------] 1 test from ArchName
[ RUN      ] ArchName.testAttribute
[       OK ] ArchName.testAttribute (0 ms)
[----------] 1 test from ArchName (0 ms total)

[----------] 1 test from EndianStream
[ RUN      ] EndianStream.WriteArrayLE
[       OK ] EndianStream.WriteArrayLE (0 ms)
[----------] 1 test from EndianStream (0 ms total)

[----------] 1 test from Error
[ RUN      ] Error.HandleExpectedSuccess
[       OK ] Error.HandleExpectedSuccess (0 ms)
[----------] 1 test from Error (0 ms total)

...

```

</details>

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