Downgrade to XCode 13 if Rust <= 1.53 on macOS

On current macOS CI images XCode 14 is enabled by default. There's some incompatibility with
Rust <= 1.53 causing link failures.
The workaround is to revert back to XCode 13 while our MSRV is lower than 1.54.

Fixes #52.

Author: LingMan

.github/workflows/main.yml

@@ -17,17 +17,19 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         rust: [stable, nightly, '1.48']
-        exclude:
-          # TODO(#52): Investigate why this is broken
-          - os: macos-latest
-            rust: '1.48'
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
       - name: Install toolchain
         uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
+      # Workaround link failures if XCode 14 is combined with Rust <= 1.53
+      - name: Downgrade to XCode 13
+        if: ${{ matrix.os == 'macos-latest' && matrix.rust == '1.48' }}
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: '13'
       - name: Test (no features)
         run: cargo test --no-default-features
       - name: Test (all features)