WIP: github: Test the Dockerfile.cross

Run this with the non-dev version of the image, which is the
previous release, so we end up fetching a new version of llvm,
instead of reusing whatever was checked out in the dev image.

.github/workflows/docker.yml

@@ -1,5 +1,6 @@
 name: Build docker images
 on:
+  push:
   workflow_dispatch:
     inputs:
       commit:
@@ -20,6 +21,7 @@ on:
 
 jobs:
   prepare:
+    if: false
     runs-on: ubuntu-latest
     outputs:
       TAG: ${{steps.get-parameters.outputs.TAG}}
@@ -40,14 +42,11 @@ jobs:
           cat $GITHUB_OUTPUT
 
   docker-build-dev:
-    needs: [prepare]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-        with:
-          ref: ${{ (inputs.commit != '' && inputs.commit) || inputs.branch }}
       - name: Log in to Docker Hub
-        if: ${{inputs.login}}
+        if: false
         uses: docker/login-action@v3
         with:
           username: ${{secrets.DOCKER_USERNAME}}
@@ -56,16 +55,16 @@ jobs:
         uses: docker/build-push-action@v5
         with:
           context: .
-          push: ${{inputs.push}}
-          file: ./Dockerfile.dev
+          push: false
+          file: ./Dockerfile.cross
           tags: |
-            mstorsjo/llvm-mingw:dev
-            mstorsjo/llvm-mingw:dev-${{needs.prepare.outputs.TAG}}
+            mstorsjo/llvm-mingw:cross
       - name: Inspect Docker images
         run: |
           docker images
 
   docker-build:
+    if: false
     needs: [prepare]
     runs-on: ubuntu-latest
     strategy:

Dockerfile.cross

@@ -8,7 +8,7 @@
 # platform, but just copies over the runtime libraries from the existing
 # toolchain in the base docker image.
 
-ARG BASE=mstorsjo/llvm-mingw:dev
+ARG BASE=mstorsjo/llvm-mingw
 FROM $BASE
 
 RUN apt-get update -qq && \