llvm 21.1.0

LLVM 21.1.0 was released this week.  I have updated the 21.1 branches of
the llvm, clang, and lld packaging repos.  I'm thinking about doing a test
release soon (I made 20.1.8-2 stable)

Test results
LLVM:
2 warning(s) in tests
********************
Failed Tests (17):
  LLVM ::
ExecutionEngine/JITLink/Generic/all-load-multifile-archive-with-duplicate-member-filenames.test
  LLVM :: ExecutionEngine/JITLink/Generic/all-load-multifile-archive.test
  LLVM :: ExecutionEngine/JITLink/Generic/sectcreate.test
  LLVM :: ExecutionEngine/MCJIT/2003-01-15-AlignmentTest.ll
  LLVM :: ExecutionEngine/MCJIT/2003-05-06-LivenessClobber.ll
  LLVM :: ExecutionEngine/MCJIT/2003-08-15-AllocaAssertion.ll
  LLVM :: ExecutionEngine/MCJIT/2003-08-23-RegisterAllocatePhysReg.ll
  LLVM :: ExecutionEngine/MCJIT/test-loadstore.ll
  LLVM :: ExecutionEngine/OrcLazy/debug-descriptor.ll
  LLVM ::
tools/llvm-mca/X86/BtVer2/skip-unsupported-instructions-none-remain.s
  LLVM :: tools/llvm-mca/X86/BtVer2/unsupported-instruction.s
  LLVM-Unit ::
ProfileData/./ProfileDataTests.exe/ParameterizedCovMapTest/CoverageMappingTest/skip_duplicate_function_record/0
  LLVM-Unit ::
ProfileData/./ProfileDataTests.exe/ParameterizedCovMapTest/CoverageMappingTest/skip_duplicate_function_record/1
  LLVM-Unit ::
ProfileData/./ProfileDataTests.exe/ParameterizedCovMapTest/CoverageMappingTest/skip_duplicate_function_record/2
  LLVM-Unit ::
ProfileData/./ProfileDataTests.exe/ParameterizedCovMapTest/CoverageMappingTest/skip_duplicate_function_record/3
  lit :: googletest-cmd-wrapper.py
  lit :: test-output-resultdb.py


Testing Time: 1481.69s

Total Discovered Tests: 68791
  Skipped          :    55 (0.08%)
  Unsupported      :  2463 (3.58%)
  Passed           : 66062 (96.03%)
  Passed With Retry:     1 (0.00%)
  Expectedly Failed:   193 (0.28%)
  Failed           :    17 (0.02%)

(the 4 ProfileData/./ProfileDataTests.exe tests should be fixed by
https://github.com/llvm/llvm-project/pull/147118)


Clang:
2 warning(s) in tests
********************
Failed Tests (7):
  Clang :: CodeGenCXX/mingw-template-dllexport.cpp
  Clang :: Driver/fveclib.c
  Clang :: Driver/mingw-sysroot.cpp
  Clang :: Index/crash-recovery-modules.m
  Clang-Unit :: Interpreter/./ClangReplInterpreterTests.exe/22/27
  Clang-Unit ::
Interpreter/./ClangReplInterpreterTests.exe/InterpreterTest/FindMangledNameSymbol
  Clang-Unit ::
Interpreter/ExceptionTests/./ClangReplInterpreterExceptionTests.exe/0/1


Testing Time: 16359.42s

Total Discovered Tests: 47733
  Skipped          :     8 (0.02%)
  Unsupported      :   559 (1.17%)
  Passed           : 47128 (98.73%)
  Expectedly Failed:    31 (0.06%)
  Failed           :     7 (0.01%)

(the Index/crash-recovery-modules.m test deadlocks trying to acquire a
mutex in a global destructor, I guess because the crash must have happened
while the mutex was held?  anyway, had to manually kill it)


lld:
1 warning(s) in tests

Testing Time: 64.71s

Total Discovered Tests: 1105
  Unsupported:   10 (0.90%)
  Passed     : 1095 (99.10%)