main.yml: add gcc 14 testing

.github/workflows/main.yml

@@ -3,13 +3,21 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-latest
-    env:
-      FC: gfortran
-      CC: gcc
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        gcc-version: [12,14]
 
     steps:
 
+    - name: get-gcc
+      run: |
+        if [ -z $(type -P gcc-${{ matrix.gcc-version }}) ]; then
+          sudo apt-get install gcc-${{ matrix.gcc-version }}
+        fi
+        echo "CC=gcc-${{ matrix.gcc-version }}" >> $GITHUB_ENV
+        echo "FC=gfortran-${{ matrix.gcc-version }}" >> $GITHUB_ENV
+
     - name: checkout-pfunit
       uses: actions/checkout@v4
       with: