Resurrect Windows-2022 with LLVM 16 [WIP]

Changes:
- adds back Windows-2022 to test.yml matrix
- adds LLVM upgrade step to test.yml to install LLVM 16
- adds command to test.yml to fix LLVM include path
- adds macro definition to .bazelrc prefer __builtin_offsetof
- adds include path override for hrss.c in external/ssl.

Currently fails building boringssl during to include path ordering: clang headers included after MSVC ones and both contain incompatible emmintrin.h.

.bazelrc

@@ -148,6 +148,15 @@ build:windows --cxxopt='/std:c++20' --host_cxxopt='/std:c++20'
 build:windows --cxxopt='/await' --host_cxxopt='/await'
 build:windows --cxxopt='/wo4503' --host_cxxopt='/wo4503'
 build:windows --cxxopt='/DWINDOWS_LEAN_AND_MEAN' --host_cxxopt='/DWINDOWS_LEAN_AND_MEAN'
+build:windows --cxxopt='/D_CRT_USE_BUILTIN_OFFSETOF' --host_cxxopt='/D_CRT_USE_BUILTIN_OFFSETOF'
 # The `/std:c++14` argument is unused during boringssl compilation and we don't
 # want a warning when compiling each file.
 build:windows --cxxopt='-Wno-unused-command-line-argument' --host_cxxopt='-Wno-unused-command-line-argument'
+
+# The following is required on github runners temporarily due to
+# https://github.com/actions/runner-images/issues/8125#issuecomment-1691194433
+# For reasons TBD, clang in LLVM 16 is including the MSFT version emmintrin.h in
+# preference to the very packaged in LLVM 16 when compiling hrss.c. The compiler
+# command-line and environment set by Bazel is the same, modulo the LLVM version
+# strings.
+build:windows --per_file_copt='external/ssl/src/crypto/hrss/hrss\.c@-imsvcC:\\Program Files\\LLVM\\lib\\clang\\16.0.6\\include' --host_per_file_copt='external/ssl/src/crypto/hrss/hrss\.c@-imsvcC:\\Program Files\\LLVM\\lib\\clang\\16.0.6\\include'

.github/workflows/test.yml

@@ -12,14 +12,14 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [ubuntu-20.04, macos-latest] # windows-2022 disabled due to actions/runner-images#812
+        os: [ubuntu-20.04, macos-latest, windows-2022]
         include:
           - os-name: linux
             os: ubuntu-20.04
           - os-name: macOS
             os: macos-latest
-          # - os-name: windows
-          #   os: windows-2022
+          - os-name: windows
+            os: windows-2022
     runs-on: ${{ matrix.os }}
     name: test (${{ matrix.os-name }})
     steps:
@@ -59,6 +59,10 @@ jobs:
         run: |
             [System.IO.File]::WriteAllLines((Join-Path -Path $env:USERPROFILE -ChildPath '.bazelrc'), 'startup --output_user_root=C:/tmp')
             [System.IO.File]::WriteAllLines((Join-Path -Path $env:USERPROFILE -ChildPath '.bazelrc'), 'build:windows --config=windows_no_dbg')
+            # Upgrade to LLVM16, default install is currently 15 (https://github.com/actions/runner-images/issues/8125).
+            choco upgrade llvm
+            # Work around bazel clang 16 include path bug (https://github.com/bazelbuild/bazel/issues/17863)
+            Move-Item -Path "C:\Program Files\LLVM\lib\clang\16" -Destination "C:\Program Files\LLVM\lib\clang\16.0.6"
       - name: Bazel build
         # timestamps are no longer being added here, the GitHub logs include timestamps (Use
         # 'Show timestamps' on the web interface)