Merge pull request #80 from infosiftr/i386-build-context

Update "munge-i386" to add "--build-context" in "docker buildx build" lines

scripts/github-actions/munge-i386.sh

@@ -7,17 +7,20 @@ jq --arg dpkgSmokeTest '[ "$(dpkg --print-architecture)" = "amd64" ]' '
 		| select(.name | test(" [(].+[)]") | not) # ignore any existing munged builds
 		| select(.os | startswith("windows-") | not)
 		| .name += " (i386)"
+		| .meta.froms as $froms
 		| .runs.pull = ([
 			"# pull i386 variants of base images for multi-architecture testing",
 			$dpkgSmokeTest,
 			(
-				.meta.froms[]
+				$froms[]
 				| ("i386/" + . | @sh) as $i386
 				| (
 					"docker pull " + $i386,
 					"docker tag " + $i386 + " " + @sh
 				)
 			)
 		] | join("\n"))
+		# adjust "docker buildx build" lines to include appropriate "--build-context" flags (https://github.com/docker/buildx/pull/1886)
+		| .runs.build |= ( gsub("docker buildx build "; "docker buildx build " + ($froms | unique | map(@sh "--build-context \(.)=docker-image://\("i386/" + .)") | join(" ")) + " ") | gsub( "--platform[= ]linux/[^ ]+"; "--platform linux/386") )
 	]
 ' "$@"