Add support for arch specifc dockerfiles (#160)

builder.sh

@@ -220,6 +220,7 @@ function run_build() {
     local cache_tag="latest"
     local metadata
     local release="${version}"
+    local dockerfile="${build_dir}/Dockerfile"
 
     # Overwrites
     if bashio::var.has_value "${DOCKER_HUB}"; then repository="${DOCKER_HUB@L}"; fi
@@ -292,13 +293,19 @@ function run_build() {
         bashio::exit.nok "Invalid base image ${build_from}"
     fi
 
+    # Arch specific Dockerfile
+    if bashio::fs.file_exists "${build_dir}/Dockerfile.${build_arch}"; then
+        dockerfile="${build_dir}/Dockerfile.${build_arch}"
+    fi
+
     # Build image
     bashio::log.info "Run build for ${repository}/${image}:${version} with platform ${docker_platform}"
-    docker buildx build --pull -t "${repository}/${image}:${version}" \
+    docker buildx build --pull --tag "${repository}/${image}:${version}" \
         --platform "${docker_platform}" \
         --build-arg "BUILD_FROM=${build_from}" \
         --build-arg "BUILD_VERSION=${version}" \
         --build-arg "BUILD_ARCH=${build_arch}" \
+        --file "${dockerfile}" \
         "${docker_cli[@]}" \
         "${build_dir}"