Update CI: add windows and macOS; Closes #2.

Author: Carlos Une

.github/workflows/fpm.yml

@@ -3,18 +3,40 @@ name: fpm
 on: [push, pull_request]
 
 jobs:
-  gfortran:
-    runs-on: ubuntu-latest
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        gcc_v: [10] # Version of GFortran we want to use.
+        include:
+        - os: ubuntu-latest
+          os-arch: linux-x86_64
+
+        - os: macos-latest
+          os-arch: macos-x86_64
+
+        - os: windows-latest
+          os-arch: windows-x86_64
 
     env:
       FC: gfortran
-      GCC_V: 10
+      GCC_V: ${{ matrix.gcc_v }}
 
     steps:
     - name: Checkout code
       uses: actions/checkout@v1
 
-    - name: Install gfortran
+    - name: Install GFortran macOS
+      if: contains(matrix.os, 'macos')
+      run: |
+        ln -s /usr/local/bin/gfortran-${GCC_V} /usr/local/bin/gfortran
+        which gfortran-${GCC_V}
+        which gfortran
+
+    - name: Install GFortran Linux
+      if: contains(matrix.os, 'ubuntu')
       run: |
         sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-${GCC_V} 100 \
         --slave /usr/bin/gfortran gfortran /usr/bin/gfortran-${GCC_V} \
@@ -36,3 +58,4 @@ jobs:
         fpm run --example example_lmder1
         fpm run --example example_lmdif1
         fpm run --example example_primes
+        fpm run --example example_hybrd1