Add windows and linux cross.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

dockerfiles/Dockerfile.cross

@@ -7,11 +7,10 @@ RUN     sed -ri "s/(httpredir|deb).debian.org/$APT_MIRROR/g" /etc/apt/sources.li
 
 RUN     apt-get update && apt-get install -y \
             libltdl-dev \
+            gcc-mingw-w64 \
+            parallel \
             ;
 
-#            build-essential \ 
-#            binutils-mingw-w64 gcc-mingw-w64
-
 RUN     go get github.com/mitchellh/gox && \
         cp /go/bin/gox /usr/bin && \
         rm -rf /go/src/* /go/pkg/* /go/bin/*

scripts/build/cross

@@ -2,20 +2,8 @@
 
 set -eu -o pipefail
 
-source ./scripts/build/.variables
+export BUILDDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-# Wow, gox doesn't like extra spaces between these strings...
-CROSS_OSARCH="\
-windows/amd64"
-
-#darwin/amd64 \
-#linux/amd64 \
-#linux/arm \
-
-# Currently broken
-# linux/ppc64le \
-
-gox -output build/docker-{{.OS}}-{{.Arch}} \
-    -osarch "${CROSS_OSARCH}" \
-	--ldflags "${LDFLAGS}" \
-	${SOURCE}
+SHELL=/bin/bash parallel ::: \
+    "$BUILDDIR/linux-cross" \
+    "$BUILDDIR/windows"

scripts/build/linux-cross

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+#
+# Build static linux binary for multiple architectures
+#
+
+set -eu -o pipefail
+
+source ./scripts/build/.variables
+
+CROSS_OSARCH="linux/amd64 linux/arm"
+
+# Compile is broken
+# linux/ppc64le
+
+# Not yet supported by gox
+# linux/s390x
+
+gox -output build/docker-{{.OS}}-{{.Arch}} \
+    -osarch "${CROSS_OSARCH}" \
+	--ldflags "${LDFLAGS}" \
+	"${SOURCE}"

scripts/build/windows

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+#
+# Build a windows binary from linux
+#
+
+set -eu -o pipefail
+
+source ./scripts/build/.variables
+
+export CC=x86_64-w64-mingw32-gcc
+export CGO_ENABLED=1
+export GOOS=windows
+export GOARCH=amd64
+
+# Override TARGET
+export TARGET="build/docker-windows-amd64"
+
+# TODO: -tags pkcs11
+go build -o "${TARGET}" --ldflags "${LDFLAGS}" "${SOURCE}"