Datawire build-aux

This is a collection of Makefile snippets (and associated utilities) for use in Datawire projects.

It has the following downsides:

1. It does not support out-of-tree builds.
2. It has no notion of nesting. You cannot cd to a sub-directory, run make, and have it just build the stuff in that directory.
3. It has no notion of nesting. If you want per-directory build descriptions, you'll have to build that functionality yourself, or offload it to a separate build-system, like go or setup.py.
4. Most of the .mk snippets have a hard dependency on the go program being in PATH, even if none of the sources are Go.

If any of those are a bummer, but you still want the "Make snippets in a ./build-aux/ folder" concept, consider Autothing (which has the downsides that it requires GNU Make 3.82 or above, and is slow).

At Datawire, those are good trade-offs, since:

• We're mostly a Python and Go shop (we don't care about #2 or #3, and only care about #4 for Python-only projects).
• I've never heard anyone here even mention out-of-tree builds (#1).
• We need to support macOS (which still ships GNU Make 3.81, as it's the last GPLv2 version) (so Autothing is ruled out).

How to use

Add build-aux.git as build-aux/ in the git repository of the project that you want to use this from. I recommend that you do this using git subtree, but git submodule is fine too.

Then, in your Makefile, write include build-aux/FOO.mk for each common bit of functionality that you want to make use of.

Using git-subtree to manage ./build-aux/

• Start using build-aux:

  $ git subtree add --squash --prefix=build-aux git@github.com:datawire/build-aux.git master

• Update to latest build-aux:

  $ ./build-aux/build-aux-pull

• Push "vendored" changes upstream to build-aux.git:

  $ ./build-aux/build-aux-push

Documentation

• Each .mk snippet contains a reference-quality header comment identifying
  • any "eager" inputs (mostly variables); these must be defined before including the .mk file.
  • any "lazy" inputs (mostly variables); these may be defined before or after including the .mk file.
  • any outputs (targets, variables)
  • which targets from other snippets it hooks in to (mostly hooking in to common.mk targets)
• docs/intro.md is an introduction to big-picture ideas in *.mk snippets.
• docs/golang.md discusses support for building software written in Go.
• docs/testing.md discusses adding tests to make check.
• HACKING.md has guidelines for contributing to build-aux.git.