macOS: patch libgfortran

.github/workflows/CI.yml

@@ -59,6 +59,32 @@ jobs:
       with:
         fpm-version: 'v0.8.0'
 
+    # Backport gfortran shared libraries to version 9 folder. This is necessary because the macOS release of fpm 
+    # 0.10.0 used for bootstrapping has these paths hardcoded in the executable.
+    - name: MacOS patch libgfortran
+      if: contains(matrix.os, 'macos') && !contains(matrix.toolchain.version, '10')
+      run: |
+        which gfortran-${{ matrix.toolchain.version }}
+        which gfortran
+        mkdir /usr/local/opt/gcc@10
+        mkdir /usr/local/opt/gcc@10/lib
+        mkdir /usr/local/opt/gcc@10/lib/gcc
+        mkdir /usr/local/opt/gcc@10/lib/gcc/10
+        mkdir /usr/local/lib/gcc/10
+        ln -fs /usr/local/opt/gcc@${{ matrix.toolchain.version }}/lib/gcc/${{ matrix.toolchain.version }}/libquadmath.0.dylib /usr/local/opt/gcc@10/lib/gcc/10/libquadmath.0.dylib 
+        ln -fs /usr/local/opt/gcc@${{ matrix.toolchain.version }}/lib/gcc/${{ matrix.toolchain.version }}/libgfortran.5.dylib /usr/local/opt/gcc@10/lib/gcc/10/libgfortran.5.dylib
+        ln -fs /usr/local/lib/gcc/${{ matrix.toolchain.version }}/libgcc_s.1.dylib /usr/local/lib/gcc/10/libgcc_s.1.dylib
+
+    # gcc and g++ will point to clang/clang++: use versioned alias for fpm
+    - name: MacOS patch C and C++ compilers
+      if: contains(matrix.os, 'macos')
+      run: |
+        echo "CC=gcc-${{ matrix.toolchain.version }}" >> $GITHUB_ENV
+        echo "FPM_CC=gcc-${{ matrix.toolchain.version }}" >> $GITHUB_ENV
+        echo "CXX=g++-${{ matrix.toolchain.version }}" >> $GITHUB_ENV
+        echo "FPM_CXX=g++-${{ matrix.toolchain.version }}" >> $GITHUB_ENV
+        echo "FPM_LDFLAGS=-lstdc++" >> $GITHUB_ENV
+
     - name: Remove fpm from path
       shell: bash
       run: |
@@ -113,11 +139,6 @@ jobs:
       env:
         REGEX: '[0-9]\{1,4\}\.[0-9]\{1,4\}\.[0-9]\{1,4\}'
 
-    - name: Build example packages
-      shell: bash
-      run: |
-        ci/run_tests.sh "${{ env.FPM }}"
-
     - name: Build Fortran fpm
       shell: bash
       run: |