Install custom OpenMP runtime for Apple clang 17

Author: aitap

.github/workflows/R-CMD-check.yaml

@@ -70,6 +70,18 @@ jobs:
         with:
           type: 'minimal'
 
+      - name: Intall and configure OpenMP runtime
+        if: runner.os == 'macOS'
+        run: |
+          if clang --version | grep 'clang version 17'; then
+            curl -O https://mac.r-project.org/openmp/openmp-19.1.0-darwin20-Release.tar.gz
+            sudo tar fvvxz openmp-19.1.0-darwin20-Release.tar.gz -C /
+            rm -f openmp-19.1.0-darwin20-Release.tar.gz
+            echo 'PKG_CFLAGS=-Xclang -fopenmp' >> $GITHUB_ENV
+            # Not the R-bundled -lomp, but our custom file installed just now
+            echo 'PKG_LIBS=/usr/local/lib/libomp.dylib' >> $GITHUB_ENV
+          fi # otherwise R-bundled runtime is fine
+
       - name: Install dependencies
         run: |
           remotes::install_deps(dependencies = TRUE)