[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-sie-ubuntu-fast` running on `sie-linux-worker` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/36989

<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/8/52' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/unittests/Support/./SupportTests-LLVM-Unit-1027112-8-52.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=52 GTEST_SHARD_INDEX=8 /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/unittests/Support/./SupportTests
--


Note: This is test shard 9 of 52.
[==========] Running 32 tests from 32 test suites.
[----------] Global test environment set-up.
[----------] 1 test from AddressRangeTest
[ RUN      ] AddressRangeTest.TestRangesMapRandom
[       OK ] AddressRangeTest.TestRangesMapRandom (0 ms)
[----------] 1 test from AddressRangeTest (0 ms total)

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

[----------] 1 test from BalancedPartitioningTest
[ RUN      ] BalancedPartitioningTest.Large
[       OK ] BalancedPartitioningTest.Large (322 ms)
[----------] 1 test from BalancedPartitioningTest (322 ms total)

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

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

[----------] 1 test from CRCTest
[ RUN      ] CRCTest.CRC32
[       OK ] CRCTest.CRC32 (0 ms)
[----------] 1 test from CRCTest (0 ms total)

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

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

...

```

</details>

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