(ci) Try testing against minimal libc version.

.github/workflows/main.yml

@@ -68,10 +68,17 @@ jobs:
           - i686-unknown-linux-musl
           - x86_64-unknown-linux-gnu
           - x86_64-unknown-linux-musl
+          - x86_64-linux-android
     steps:
     - name: Checkout
       uses: actions/checkout@v3
 
+    # We need nightly for -Zminimal-versions
+    - name: Install toolchain
+      uses: dtolnay/rust-toolchain@nightly
+      with:
+        target: ${{ matrix.target }}
+
     - name: Install toolchain
       uses: dtolnay/rust-toolchain@stable
       with:
@@ -83,27 +90,18 @@ jobs:
         sudo apt update -yqq
         sudo apt install gcc-multilib
 
-    - name: Run tests
-      run: cargo test --all-features --target ${{ matrix.target }}
-
-  # Just make sure it builds. Not tests running.
-  test-android:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        target:
-          - x86_64-linux-android
-    steps:
-    - name: Checkout
-      uses: actions/checkout@v3
+    # Make sure we're testing against the minimal libc version.
+    - name: Generate Cargo.lock
+      run: cargo +nightly update -Zminimal-versions
 
-    - name: Install toolchain
-      uses: dtolnay/rust-toolchain@stable
-      with:
-        target: ${{ matrix.target }}
+    - name: Run tests
+      if: ${{ !contains(matrix.target, 'android') }}
+      run: cargo test --locked --all-features --target ${{ matrix.target }}
 
-    - name: Build
-      run: cargo build --all-features --target ${{ matrix.target }}
+    # Just make sure it builds. Not tests running.
+    - name: Run tests
+      if: ${{ contains(matrix.target, 'android') }}
+      run: cargo build --locked --all-features --target ${{ matrix.target }}
 
   check-stub:
     runs-on: ubuntu-latest