Rewrite build system for new versions and Heroku stacks

This allows new versions to be built for uploading by running
`make VERSION=5.0.1` rather than updating the hard coded version in
multiple places. I've also added support for building against either the
legacy cedar-14 architecture or heroku-16. While versions built on
cedar-14 appear to run on heroku-16, the newer stack should also mean a
newer and better tool chain.

I've removed the Dockerfile and switched to using Heroku's docker images
directly as this removes the need for cleaning them up afterwards. It
possibly makes debugging harder but having build.sh available should
avoid some of that.

Fixes #2
Fixes #7
Fixes #13

Makefile

@@ -1,21 +1,33 @@
-default: dist/jemalloc-5.0.0-1.tar.gz
+default: heroku-16 cedar
 
-dist/jemalloc-5.0.0-1.tar.gz: jemalloc-cedar
-	docker cp $<:/tmp/jemalloc-cedar.tar.gz .
-	mkdir -p $$(dirname $@)
-	mv jemalloc-cedar.tar.gz $@
+VERSION := 5.0.1
+ROOT_DIR := $(shell dirname $(abspath $(lastword $(MAKEFILE_LIST))))
 
 clean:
 	rm -rf src/ dist/
-	-docker rm jemalloc-cedar
 
-src/jemalloc.tar.bz2:
+# Download missing source archives to ./src/
+src/jemalloc-%.tar.bz2:
 	mkdir -p $$(dirname $@)
-	curl -sL https://github.com/jemalloc/jemalloc/releases/download/5.0.0/jemalloc-5.0.0.tar.bz2 -o $@
+	curl -fsL https://github.com/jemalloc/jemalloc/releases/download/$*/jemalloc-$*.tar.bz2 -o $@
+
+.PHONY: cedar-14 heroku-16
+
+# Build for cedar stack (deprecated)
+cedar-14: src/jemalloc-$(VERSION).tar.bz2
+	docker run -it --volume="$(ROOT_DIR):/wrk" \
+		heroku/cedar:14 /wrk/build.sh $(VERSION) cedar-14
 
-.PHONY: jemalloc-cedar
+# Build for heroku-16 stack
+heroku-16: src/jemalloc-$(VERSION).tar.bz2
+	docker run -it --volume="$(ROOT_DIR):/wrk" \
+		heroku/heroku:16-build /wrk/build.sh $(VERSION) heroku-16
 
-jemalloc-cedar: src/jemalloc.tar.bz2
-	docker build --rm -t mojodna/$@ .
-	-docker rm $@
-	docker run --name $@ mojodna/$@ /bin/echo $@
+# Build recent releases for heroku-16 and cedar
+all:
+	$(MAKE) cedar-14 VERSION=3.6.0
+	$(MAKE) cedar-14 VERSION=4.5.0
+	$(MAKE) cedar-14 VERSION=5.0.1
+	$(MAKE) heroku-16 VERSION=3.6.0
+	$(MAKE) heroku-16 VERSION=4.5.0
+	$(MAKE) heroku-16 VERSION=5.0.1

README.md

@@ -43,7 +43,7 @@ This uses Docker to build against Heroku
 [stack-image](https://github.com/heroku/stack-images)-like images.
 
 ```bash
-make
+make VERSION=5.0.1
 ```
 
-Artifacts will be dropped in `dist/`.  See `Dockerfile`s for build options.
+Artifacts will be dropped in `dist/` based on Heroku stack and jemalloc version.

build.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# usage: build [version] [stack]
+set -e
+
+version=$1
+stack=$2
+build=`mktemp -d`
+
+tar -C $build --strip-components=1 -xj -f /wrk/src/jemalloc-$version.tar.bz2
+
+cd $build
+./configure --prefix=/app/vendor/jemalloc
+make install_bin install_include install_lib_shared install_lib_static
+
+# Bundle and compress the compiled library
+mkdir -p /wrk/dist/$stack
+tar -C /app/vendor/jemalloc -zc -f /wrk/dist/$stack/jemalloc-$version.tar.gz .