Don't try to install musl-tools if it's already installed

Changes.md

@@ -1,3 +1,15 @@
+## 1.0.0
+
+The addition of caching is a significant behavior change for this action, so the version has been
+bumped to v1.0.0 because of this change.
+
+- This action will now configure and use `Swatinem/rust-cache` by default for you. It will include
+  the `target` parameter as part of the cache key automatically. Suggested by @jennydaman (Jennings
+  Zhang). GH #23.
+- This action now validates its input and will exit early if they are not valid. GH #35.
+- When compiling for `musl` targets, this action will not try to reinstall the `musl-tools` package
+  if it's already installed.
+
 ## 1.0.0-beta1 - 2024-12-21
 
 The addition of caching is a significant behavior change for this action, so the version has been

action.yml

@@ -111,7 +111,12 @@ runs:
         GITHUB_TOKEN: ${{ inputs.GITHUB_TOKEN }}
     - name: Install musl-tools on Linux if target includes "musl"
       shell: bash
-      run: sudo apt-get update --yes && sudo apt-get install --yes musl-tools
+      run: |
+        if dpkg -l musl-tools | grep -q "^ii\s*musl-tools"; then
+            exit 0
+        fi
+        sudo apt-get update --yes && \
+            sudo apt-get install --yes musl-tools
       if: steps.determine-cross-compile.outputs.needs-cross != 'true' && contains(inputs.target, 'musl')
     - name: Set build command
       id: set-build-command