Cache the ccache dir

.github/workflows/reusable-build-test-config.yml

@@ -116,10 +116,16 @@ jobs:
             ${CMAKE_ARGS} \
             ..
 
+      - name: Get ccache directory
+        if: ${{ runner.os == 'Linux' }}
+        id: ccache
+        run: echo "dir=$(ccache -k cache_dir)" >> $GITHUB_OUTPUT
+
       - name: Restore build objects
+        if: ${{ runner.os == 'Linux' }}
         uses: actions/cache/restore@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
         with:
-          path: "${{ inputs.build_dir }}/**/*.o"
+          path: ${{ steps.ccache.outputs.dir }}
           key: ${{ inputs.config_name }}
 
       - name: Print out ccache statistics before building
@@ -142,9 +148,10 @@ jobs:
         run: ccache -s
 
       - name: Save build objects
+        if: ${{ runner.os == 'Linux' }}
         uses: actions/cache/save@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
         with:
-          path: "${{ inputs.build_dir }}/**/*.o"
+          path: ${{ steps.ccache.outputs.dir }}
           key: ${{ inputs.config_name }}
 
       - name: Upload rippled artifact (Linux)