Trying alternate macOS config for openmp

Author: eddelbuettel

.github/workflows/ci.yaml

@@ -17,6 +17,7 @@ jobs:
           - { name: container, os: ubuntu-latest, container: rocker/r2u4ci }
           - { name: macos,     os: macos-latest,  openmp: yes }
           - { name: macos,     os: macos-latest,  openmp: no }
+          - { name: macos,     os: macos-latest,  openmp: alt }
           #- { name: ubuntu,    os: ubuntu-latest }
 
 
@@ -39,17 +40,24 @@ jobs:
           CPPFLAGS += -Xclang -fopenmp
           LDFLAGS += -lomp
           EOF
-
-      - name: Show config on macOS
-        if: ${{ matrix.os == 'macos-latest' && matrix.openmp == 'yes' }}
-        run: |
           cat ~/.R/Makevars
           echo -n "R CMD config CXX: "; R CMD config CXX
           echo -n "R CMD config CPPFLAGS: "; R CMD config CPPFLAGS
           echo -n "R CMD config LDFLAGS: "; R CMD config LDFLAGS
           echo -n "R CMD config SHLIB_CXXLD: "; R CMD config SHLIB_CXXLD
           echo -n "R CMD config SHLIB_CXXLDFLAGS: "; R CMD config SHLIB_CXXLDFLAGS
 
+      - name: Alternate OpenMP for macOS
+        if: ${{ matrix.os == 'macos-latest' && matrix.openmp == 'alt' }}
+        run: |
+          curl -O https://mac.r-project.org/openmp/openmp-17.0.6-darwin20-Release.tar.gz
+          sudo tar fvxz openmp-17.0.6-darwin20-Release.tar.gz -C /
+          rm openmp-17.0.6-darwin20-Release.tar.gz
+          sudo xcode-select -s /Applications/Xcode_16.2.app
+          echo "MACOSX_DEPLOYMENT_TARGET=11.0" >> $GITHUB_ENV
+          echo "xcode is set: $(xcode-select --print-path)"
+          echo "using SDK: $(xcrun --show-sdk-version)"
+
       - name: Configure
         run: ./configure; cat src/Makevars
 
@@ -59,7 +67,7 @@ jobs:
       - name: Test
         run: ./run.sh run_tests
 
-      - name: Install
+      - name: Install and Verify on macOS
         if: ${{ matrix.os == 'macos-latest' }}
         run: |
           R CMD INSTALL .