Fix cryptography builds on Windows. (#2704)

More work towards #2658.

Author: jsirois

.github/workflows/ci.yml

@@ -285,6 +285,11 @@ jobs:
         if: env.SSH_PRIVATE_KEY != ''
         with:
           ssh-private-key: ${{ env.SSH_PRIVATE_KEY }}
+      - name: Install OpenSSL (Windows)
+        shell: powershell
+        run: |
+          echo "VCPKG_ROOT=$env:VCPKG_INSTALLATION_ROOT" | Out-File -FilePath $env:GITHUB_ENV -Append
+          vcpkg install openssl:x64-windows-static-md
       - name: Run Tests
         uses: pex-tool/actions/run-tox@c53dadd8b410bbd66480de91067e9e45d2b3af38
         continue-on-error: true

tox.ini

@@ -52,6 +52,7 @@ passenv =
     # Mac (Homebrew) needs these.
     HOME
     # Windows needs these.
+    OPENSSL_DIR
     PATHEXT
     USER
     USERNAME