Makefile target to enable parallel jobs

- fixed dependencies order and renamed Makefile target
- extracted docker run params into DOCKER_RUN_OPTS
- crossbinary-default contains 64bit Linux, Win and Darwin
- crossbinary-others contains 32bit Linux, Win, Darwin and 32/64bit *bsd
- added dependencies to crossbinary-default and crossbinary-others targets

script/crossbinary-default

@@ -0,0 +1,40 @@
+#!/bin/bash
+set -e
+
+if ! test -e autogen/gen.go; then
+	echo >&2 'error: generate must be run before crossbinary'
+	false
+fi
+
+if [ -z "$VERSION" ]; then
+    VERSION=$(git rev-parse HEAD)
+fi
+
+if [ -z "$CODENAME" ]; then
+    CODENAME=cheddar
+fi
+
+if [ -z "$DATE" ]; then
+    DATE=$(date -u '+%Y-%m-%d_%I:%M:%S%p')
+fi
+
+# Build 386 amd64 binaries
+OS_PLATFORM_ARG=(linux windows darwin)
+OS_ARCH_ARG=(amd64)
+for OS in ${OS_PLATFORM_ARG[@]}; do
+  for ARCH in ${OS_ARCH_ARG[@]}; do
+    echo "Building binary for $OS/$ARCH..."
+    GOARCH=$ARCH GOOS=$OS CGO_ENABLED=0 go build -ldflags "-s -w -X github.com/containous/traefik/version.Version=$VERSION -X github.com/containous/traefik/version.Codename=$CODENAME -X github.com/containous/traefik/version.BuildDate=$DATE" -o "dist/traefik_$OS-$ARCH" ./cmd/traefik/
+  done
+done
+
+
+# Build arm64 binaries
+OS_PLATFORM_ARG=(linux)
+OS_ARCH_ARG=(arm64)
+for OS in ${OS_PLATFORM_ARG[@]}; do
+  for ARCH in ${OS_ARCH_ARG[@]}; do
+    echo "Building binary for $OS/$ARCH..."
+    GOARCH=$ARCH GOOS=$OS CGO_ENABLED=0 go build -ldflags "-s -w -X github.com/containous/traefik/version.Version=$VERSION -X github.com/containous/traefik/version.Codename=$CODENAME -X github.com/containous/traefik/version.BuildDate=$DATE" -o "dist/traefik_$OS-$ARCH" ./cmd/traefik/
+  done
+done