Trying to add support for building on macos and windows as well

Author: blurpy

.github/workflows/cmake.yml

@@ -8,11 +8,14 @@ env:
 
 jobs:
   build:
+    strategy:
+      matrix:
+        platform: [ubuntu-latest, macos-latest, windows-latest]
     # The CMake configure and build commands are platform agnostic and should work equally
     # well on Windows or Mac.  You can convert this to a matrix build if you need
     # cross-platform coverage.
     # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.platform }}
 
     steps:
     - uses: actions/checkout@v2