* [llvm] update to 12.0.0, enable zlib and libxml2

* [llvm] disable libxml2 by default, arm64-windows should be supported

* [llvm] try to fix build with ffi on Windows #17663

* [llvm] re-enable libxml2

* [llvm] fix formatting

* [llvm] overwrite version

* [mesa] update to v21.1.0

* [llvm] update ci.baseline

* [halide] update to the latest master commit

* [llvm] disable libxml2 port until complete PR #15390

* update versions

* [llvm] fix disabling of external libraries

* update version

* update ci.baseline

* update ci.baseline

* fix typo

* [llvm] fix libxml2 (depends on #17945)

* revert "[halide] update to the latest master commit"

* update versions

* [halide] fix zlib dependency for tools

* update versions

* [halide] update to official release v12.0.0

* update versions

* [halide] update to v12.0.1

* update version

* [mesa] remove llvm from defaults

* update version

* update ci.baseline

* [mesa] update to v21.1.2 and fix build with LLVM on Windows

* [llvm] allow to build libunwind project on Windows

* update versions

* [mesa] update ci.baseline.txt to disable x64-windows-static-md, may be fixed in the PR #18495

* [vcpkg] allow to use semicolons in COMMAND argument

* [llvm] update to 11.0.0

* [vcpkg] use latest version

* [vcpkg] allow to use semicolons in OPTIONS

* fix vcpkg_fixup_cmake_targets

* [llvm] fix more install paths, add /bigobj option, fix up CMake targets

* Apply suggestions from code review

* [llvm] fix clang, flang, lld, mlir and polly CMake targets

* [llvm] remove empty include directory /include/flang/Config

* [llvm] Flang requires C++17

* [llvm] add /Zc:__cplusplus

* [llvm] remove empty include directory include/clang-tidy/plugin

* [llvm] try to fix ClangConfig.cmake, LLVMConfig.cmake, LLDConfig.cmake etc. with patch

* [llvm] set tools install dir to tools/llvm

* [aws-sdk-cpp] fix build after changes in vcpkg_configure_cmake.cmake

* [llvm] disable Flang and OpenMP on Windows

Co-authored-by: Nicole Mazzuca <mazzucan@outlook.com>