iwyu.yml: generate and use macOS mapping file [skip ci] (danmar#7465)

Author: firewave

.github/workflows/iwyu.yml

@@ -26,6 +26,7 @@ jobs:
           - os: macos-13
             image: ""
             stdlib: libc++  # no libstdc++ on macOS
+            mapping_file_opt: '-Xiwyu --mapping_file=$(realpath ./macos.imp)'
       fail-fast: false
 
     runs-on: ${{ matrix.os }}
@@ -110,6 +111,13 @@ jobs:
           install-deps: false
           cache: true
 
+      - name: Build macOS mappings
+        run: |
+          set -x
+
+          wget https://raw.githubusercontent.com/include-what-you-use/include-what-you-use/master/mapgen/iwyu-mapgen-apple-libc.py
+          python3 iwyu-mapgen-apple-libc.py $(xcrun --show-sdk-path)/usr/include > macos.imp
+
       - name: Prepare CMake
         run: |
           # TODO: why does it build dmake in the next step?
@@ -137,14 +145,22 @@ jobs:
         run: |
           # -isystem/usr/lib/clang/17/include
           # TODO: remove -stdlib= - it should have been taken from the compilation database
-          iwyu_tool -p cmake.output -j $(nproc) -- -w -Xiwyu --max_line_length=1024 -Xiwyu --comment_style=long -Xiwyu --quoted_includes_first -Xiwyu --update_comments -stdlib=${{ matrix.stdlib }} > iwyu.log
+          iwyu_tool -p cmake.output -j $(nproc) -- -w -Xiwyu --max_line_length=1024 -Xiwyu --comment_style=long -Xiwyu --quoted_includes_first -Xiwyu --update_comments -stdlib=${{ matrix.stdlib }} ${{ matrix.mapping_file_opt }} > iwyu.log
 
       - uses: actions/upload-artifact@v4
         if: success() || failure()
         with:
           name: Compilation Database (include-what-you-use - ${{ matrix.os }} ${{ matrix.stdlib }})
           path: ./cmake.output/compile_commands.json
 
+      - uses: actions/upload-artifact@v4
+        if: ${{ contains(matrix.os, 'macos') && (success() || failure()) }}
+        with:
+          name: macOS Mappings
+          path: |
+            ./iwyu-mapgen-apple-libc.py
+            ./macos.imp
+
       - uses: actions/upload-artifact@v4
         if: success() || failure()
         with: