Add cross compilation scripts

build.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+# this script is intended to run inside the docker container
+# e.g. docker-compose run dbmate ./build.sh
+
+set -ex
+
+BUILD_FLAGS="-ldflags -s"
+
+rm -rf dist
+
+GOOS=linux GOARCH=386 go build $BUILD_FLAGS \
+  -o dist/dbmate-linux-i386
+GOOS=linux GOARCH=amd64 go build $BUILD_FLAGS \
+  -o dist/dbmate-linux-amd64
+GOOS=darwin GOARCH=386 CC=o32-clang CXX=o32-clang++ go build $BUILD_FLAGS \
+  -o dist/dbmate-osx-i386
+GOOS=darwin GOARCH=amd64 CC=o64-clang CXX=o64-clang++ go build $BUILD_FLAGS \
+  -o dist/dbmate-osx-amd64