[clang] [llvm] Hurd: Add x86_64 support (PR #78065)

[Florian Mayer via cfe-commits]

fmayer wrote:

This broke Sanitizer bots:


```
[5/25] Building CXX object tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Hurd.cpp.o
FAILED: tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Hurd.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /b/sanitizer-aarch64-linux/build/llvm_build0/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/sanitizer-aarch64-linux/build/build_symbolizer/tools/clang/lib/Driver -I/b/sanitizer-aarch64-linux/build/llvm-project/clang/lib/Driver -I/b/sanitizer-aarch64-linux/build/llvm-project/clang/include -I/b/sanitizer-aarch64-linux/build/build_symbolizer/tools/clang/include -I/b/sanitizer-aarch64-linux/build/build_symbolizer/include -I/b/sanitizer-aarch64-linux/build/llvm-project/llvm/include -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 -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -Wno-nested-anon-types -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Hurd.cpp.o -MF tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Hurd.cpp.o.d -o tools/clang/lib/Driver/CMakeFiles/obj.clangDriver.dir/ToolChains/Hurd.cpp.o -c /b/sanitizer-aarch64-linux/build/llvm-project/clang/lib/Driver/ToolChains/Hurd.cpp
/b/sanitizer-aarch64-linux/build/llvm-project/clang/lib/Driver/ToolChains/Hurd.cpp:137:11: error: 60 enumeration values not handled in switch: 'UnknownArch', 'arm', 'armeb'... [-Werror,-Wswitch]
  137 |   switch (getArch()) {
      |           ^~~~~~~~~
1 error generated.
```

https://github.com/llvm/llvm-project/pull/78065