build golang on alpine linux

#!/bin/bash
export GOLANG_VERSION=1.12.5
apk add --virtual .build-deps musl-dev go gcc openssl bash
GOROOT_BOOTSTRAP="$(go env GOROOT)"
wget -O go.tgz "https://golang.org/dl/go$GOLANG_VERSION.src.tar.gz"
tar -C /usr/local -xzf go.tgz
rm go.tgz
cd /usr/local/go/src
./make.bash
rm -rf /usr/local/go/pkg/bootstrap /usr/local/go/pkg/obj
apk del .build-deps