[clang] [lld] [llvm] [llvm][clang][lld][COFF] Add support for case-insensitive path lookup (PR #178585)

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github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 3095 tests passed
* 7 tests skipped

All executed tests passed, but another part of the build **failed**. Click on a failure below to see the details.

<details>
<summary>lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/SafeStack.cpp.o (Likely Already Failing)</summary>
This test is already failing at the base commit.

```
FAILED: lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/SafeStack.cpp.o
sccache /opt/llvm/bin/clang++ -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/CodeGen -I/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/CodeGen -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/include -I/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include -gmlt -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wno-pass-failed -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -UNDEBUG -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/SafeStack.cpp.o -MF lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/SafeStack.cpp.o.d -o lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/SafeStack.cpp.o -c /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/CodeGen/SafeStack.cpp
/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/CodeGen/SafeStack.cpp:666:11: error: unused variable 'Ty' [-Werror,-Wunused-variable]
666 |     Type *Ty = AI->getAllocatedType();
|           ^~
1 error generated.
```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/178585