Fix issue with installation of gfortran 11

On my own repo I had issues running programs compiled with gfortran 11 in CI.
It turned out they were being compiled with gfortran 11, but were picking up
libgfortran-5.dll from /c/mingw64/bin, which is from gcc 12, at runtime, and would
crash.

I've modified hw.90 to reproduce the problem as minimally as I can, although perhaps
someone else can make it more minimal.

I've temporarily added an intentionally failing action to demonstrate the issue,
obviously we would remove that ahead of merging.

I also added gcc 12 to the test matrix. It claims to be supported so it seems only
logical to test it in addition to 11 and 13.

.github/actions/test-fc/action.yml

@@ -39,7 +39,23 @@ runs:
             args="-L/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib"
           fi
         fi
+        
+        ${{ env.FC }} $args -o hw hw.f90
+        output=$(./hw '2>&1')
+        [[ "$output" == *"hello world"* ]] && echo "$output" || (echo "Unexpected Fortran program output: $output"; exit 1)
+        rm hw
+
+    - name: Test compile (bash) (intentionally failing)
+      if: ${{ runner.os == 'Windows' && inputs.compiler == 'gcc' && inputs.version == '11' }}
+      shell: bash
+      run: |
+        set -x
 
+        # Move the old libgfortran-5.dll back to its original place.
+        mv "$RUNNER_TEMP/mingw64/libgfortran-5.dll" /c/mingw64/bin/libgfortran-5.dll 
+        # Confirm that we find the gcc12 one ahead of the gcc11 one.
+        which -a libgfortran-5.dll
+        
         ${{ env.FC }} $args -o hw hw.f90
         output=$(./hw '2>&1')
         [[ "$output" == *"hello world"* ]] && echo "$output" || (echo "Unexpected Fortran program output: $output"; exit 1)

.github/workflows/test.yml

@@ -30,6 +30,8 @@ jobs:
           - windows-2022
           - windows-2019
         toolchain:
+          - {compiler: gcc, version: 11}
+          - {compiler: gcc, version: 12}
           - {compiler: gcc, version: 13}
           - {compiler: intel, version: '2023.2'}
           - {compiler: intel-classic, version: '2021.10'}

hw.f90

@@ -1,3 +1,22 @@
-program hello
-  print *, "hello world"
-end program hello
+program bobyqa_exmp
+implicit none
+
+logical :: parent_logical_array(20)
+integer(4), allocatable :: locations(:)
+
+locations = true_locations(parent_logical_array)
+print *, "hello world"
+
+contains
+
+function true_locations(logical_array) result(location_array)
+implicit none
+logical, intent(in) :: logical_array(:)
+integer(4), allocatable :: location_array(:)
+integer(4) :: n, monotone_array(size(logical_array))
+n = count(logical_array)
+allocate(location_array(1:n))
+location_array = pack(monotone_array, mask=logical_array)
+
+end function true_locations
+end program bobyqa_exmp

setup-fortran.sh

@@ -89,6 +89,7 @@ install_gcc_choco()
     # otherwise hide preinstalled mingw compilers
     mkdir "$RUNNER_TEMP/mingw64"
     mv /c/mingw64/bin/gfortran "$RUNNER_TEMP/mingw64/gfortran"
+    mv /c/mingw64/bin/libgfortran-5.dll "$RUNNER_TEMP/mingw64/libgfortran-5.dll"
     mv /c/mingw64/bin/gcc "$RUNNER_TEMP/mingw64/gcc"
     mv /c/mingw64/bin/g++ "$RUNNER_TEMP/mingw64/g++"
     # ...and install selected version