try qemu

.github/workflows/dockerarm.yml

@@ -5,5 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@master
+      - name: prepare stuff
+        run: ./prepare.sh
       - name: Build the Docker image
         run: docker build . --file 0.18/source/Dockerfile --tag bitcoind:arm-$(date +%s)

prepare.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -e
+
+wget -N https://github.com/multiarch/qemu-user-static/releases/download/v4.0.0-5/x86_64_qemu-arm-static.tar.gz
+tar -xvf x86_64_qemu-arm-static.tar.gz
+
+docker run --rm --privileged multiarch/qemu-user-static:register