Add GitHub CI configuration

.github/workflows/fox32os-unstable.yml

@@ -0,0 +1,56 @@
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+
+name: fox32os Unstable
+
+jobs:
+  fox32os-unstable-linux:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: true
+
+      - name: Download latest fox32asm artifact
+        uses: dawidd6/action-download-artifact@v2
+        with:
+          repo: fox32-arch/fox32asm
+          workflow: fox32asm-unstable-linux.yml
+          workflow_conclusion: success
+
+      - name: Download latest fox32rom artifact
+        uses: dawidd6/action-download-artifact@v2
+        with:
+          repo: fox32-arch/fox32rom
+          workflow: fox32rom-unstable.yml
+          workflow_conclusion: success
+
+      - name: Download latest tools artifact
+        uses: dawidd6/action-download-artifact@v2
+        with:
+          repo: fox32-arch/tools
+          workflow: tools-unstable-linux.yml
+          workflow_conclusion: success
+
+      - name: Build
+        run: |
+          mkdir ../fox32rom
+          cp fox32rom.def/fox32rom.def ../fox32rom/
+          chmod +x fox32asm/fox32asm gfx2inc/gfx2inc
+          make FOX32ASM=fox32asm/fox32asm GFX2INC=gfx2inc/gfx2inc
+
+      - name: Upload fox32os.img
+        uses: actions/upload-artifact@v3
+        with:
+          name: fox32os.img
+          path: fox32os.img
+
+      - name: Upload fox32os.def
+        uses: actions/upload-artifact@v3
+        with:
+          name: fox32os.def
+          path: fox32os.def