Run build workflow in CI on the windows & macos also (#26362)

.github/workflows/build.yml

@@ -2,7 +2,7 @@ name: Build
 on:
     pull_request: {}
     push:
-        branches: [master]
+        branches: [develop, master]
 # develop pushes and repository_dispatch handled in build_develop.yaml
 env:
     # These must be set for fetchdep.sh to get the right branch
@@ -10,8 +10,25 @@ env:
     PR_NUMBER: ${{ github.event.pull_request.number }}
 jobs:
     build:
-        name: "Build"
+        name: "Build on ${{ matrix.image }}"
-        runs-on: ubuntu-latest
+        # We build on all 3 platforms to ensure we don't have any OS-specific build incompatibilities
+        strategy:
+            fail-fast: false
+            matrix:
+                image:
+                    - ubuntu-latest
+                    - windows-latest
+                    - macos-latest
+                isDevelop:
+                    - ${{ github.event_name == 'push' && github.ref_name == 'develop' }}
+                # Skip the ubuntu-latest build for the develop branch as the dedicated CD build_develop workflow handles that
+                exclude:
+                    - isDevelop: true
+                      image: ubuntu-latest
+        runs-on: ${{ matrix.image }}
+        defaults:
+            run:
+                shell: bash
         steps:
             - uses: actions/checkout@v4