ci: test windows dyn link

This requires an upstream bug-fix from cargo-c. Until there's a release
published with this fix we have to build our own copy (slow).

With this in place, we can run integration tests against client/server
binaries that dynamically link librustls.dll \o/

Author: cpu

.github/workflows/test.yaml

@@ -196,10 +196,9 @@ jobs:
         dyn_link: [ off ]
         include:
           # One build with dynamic linking.
-          # TODO(@cpu): debug broken dyn-link build on Windows.
-          # - crypto: aws-lc-rs
-          #   config: Release
-          #   dyn_link: on
+          - crypto: aws-lc-rs
+            config: Release
+            dyn_link: on
           # One build with cert_compression.
           - crypto: aws-lc-rs
             config: Release
@@ -221,13 +220,27 @@ jobs:
         with:
           arch: x64
 
+      # TODO(@cpu): switch back to binary cargo-c releases once a release with
+      #   https://github.com/lu-zero/cargo-c/pull/428 is included. This is
+      #   needed for dynamic linking support on Windows.
+      # - name: Install cargo-c
+      #
+      #  env:
+      #    LINK: https://github.com/lu-zero/cargo-c/releases/latest/download
+      #    CARGO_C_FILE: cargo-c-windows-msvc.zip
+      #  run: |
+      #    curl -L "$env:LINK/$env:CARGO_C_FILE" -o cargo-c-windows-msvc.zip
+      #    powershell -Command "Expand-Archive -Path cargo-c-windows-msvc.zip -DestinationPath $env:USERPROFILE\\.cargo\\bin -Force"
       - name: Install cargo-c
-        env:
-          LINK: https://github.com/lu-zero/cargo-c/releases/latest/download
-          CARGO_C_FILE: cargo-c-windows-msvc.zip
         run: |
-          curl -L "$env:LINK/$env:CARGO_C_FILE" -o cargo-c-windows-msvc.zip
-          powershell -Command "Expand-Archive -Path cargo-c-windows-msvc.zip -DestinationPath $env:USERPROFILE\\.cargo\\bin -Force"
+          mkdir /tmp
+          pushd /tmp
+          git clone https://github.com/lu-zero/cargo-c.git 
+          cd cargo-c
+          git fetch origin
+          git checkout msvc-def-gen
+          cargo install --path ./
+          popd
 
       - name: Configure CMake
         run: cmake -DCRYPTO_PROVIDER="${{ matrix.crypto }}" -DCERT_COMPRESSION="${{ matrix.cert_compression }}" -DDYN_LINK="${{ matrix.dyn_link }}" -S . -B build