Auto merge of #557 - servo:jdm-patch-26, r=jdm

Fix windows CI.

Equivalent of servo/mozjs#301.

Author: bors-servo

.github/workflows/rust.yml

@@ -31,10 +31,11 @@ jobs:
     - name: Install deps on windows
       if: startsWith(matrix.os, 'windows')
       run: |
-        Start-BitsTransfer -Source https://ftp.mozilla.org/pub/mozilla/libraries/win32/MozillaBuildSetup-Latest.exe -Destination ./MozillaBuildSetup.exe
+        Start-BitsTransfer -Source https://ftp.mozilla.org/pub/mozilla/libraries/win32/MozillaBuildSetup-3.4.exe -Destination ./MozillaBuildSetup.exe
         .\MozillaBuildSetup.exe /S | Out-Null
-        iwr -useb get.scoop.sh | iex
-        scoop install llvm --global
+        iwr -useb get.scoop.sh -outfile 'install.ps1'
+        .\install.ps1 -RunAsAdmin
+        scoop install [email protected] --global
         echo "C:\ProgramData\scoop\shims;C:\Users\runneradmin\scoop\shims" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
     - uses: actions-rs/toolchain@v1
       with: