message: change to older mac toolchain
diff: @@ -126,6 +126,9 @@ jobs:
  - name: Checkout repository
  uses: actions/checkout@v2
  with: {submodules: true}
  + - name: Change to older toolchain
  + if: matrix.os == 'macos'
  + run: sudo xcode-select -s "/Applications/Xcode_11.7.app"
  - name: Install Rust (${{matrix.rust}})
  uses: actions-rs/toolchain@v1
  with: {toolchain: '${{matrix.rust}}', profile: minimal, override: true}
  