Emacs Build Scripts

These are the emacs build scripts that produces the builds at http://emacsformacosx.com/.

Prerequisites

Hardware Requirements

The scripts are modular and are designed to be run on multiple build machines (or VMs) and integrate with continuous integration servers (the builds on emacsformacosx.com run from Jenkins now). This means that you can build whatever architectures you have access to.

Note that cross-compiling Emacs is (still) not possible due to the "unexec" step, which requires the binary that was built to be run. So if you want to build an old architecture (like PowerPC), you need to be running on a system that can actually execute binaries of that architecture.

XZ

Recent Emacs pretests are being distributed in .tar.xz format. The "fetch-emacs-from-ftp" script will convert from .xz to .tar.bz2 so that XZ doesn't need to be installed on every build machine. But you will need the "xz" program on the machines that runs "fetch-emacs-from-ftp". The easiest way to get it is through homebrew: "brew install xz"

XCode Command Line Tools

Building emacs requires that the XCode command line tools be installed so that some libraries (libxml2, at least) are available.

xcode-select --install

Currently, Homebrew installs a pkg-config definition for the built in libxml2, but uses deprecated paths that don't exist by default on newer MacOS versions (10.14 at least). The symptom is this error:

  CC       xml.o
xml.c:26:10: fatal error: 'libxml/tree.h' file not found
#include <libxml/tree.h>
         ^~~~~~~~~~~~~~~
1 error generated.

To fix it, run this:

sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /

Rust

The launcher is now written in Rust instead of Ruby. To build it you need Rust installed.

The Rust cargo invocations are wrapped in a Makefile that compiles both x86_64 and aarch64 and then uses Apple's lipo to combine them into a fat binary. This requires that you have Rust compiler targets installed for both x86_64 and aarch64 (Apple Silicon). This can be accomplished with (on an aarch64 (Apple Silicon) machine):

rustup target add x86_64-apple-darwin

Or on an x86_64 (Intel) mac:

rustup target add aarch64-apple-darwin

Ruby

The system Ruby from macOS 10.12 (ruby 2.3.7p456) should be able to run the scripts. If you are trying to build on an older macOS, you may need to get a more recent Ruby installed.

Usage

There are 3 scripts that are designed to be run from some sort of Continuous Integration software (the builds on http://emacsformacosx.com run from Jenkins). All three scripts know the --verbose command, and are nice and loud when it is given.

fetch-emacs-from-ftp

This takes an ftp url (ftp://ftp.gnu.org/gnu/emacs/, for example), and downloads the latest version of the Emacs source code found there. It will also convert the source from a .tar.xz to a .tar.bz2 (so that the main build VMs don't need to have "XZ" installed).

build-emacs-from-tar

This is the main build script. It takes a tar file and a "kind" (pretest, nightly, or release) as input and unpacks the tar, builds it for a single architecture, and tars up the resulting Emacs.app file.

You can tell it to build an architecture other than the default with the --arch option (--arch=powerpc or --arch=i386).

Builds of the main Emacs source repository are expected to be packaged up into tars elsewhere. http://emacsformacosx.com has a Jenkins job that pulls down the latest code and then tars it up like so:

DATE=$(date "+%Y-%m-%d_%H-%M-%S")
SHORT=$(git rev-parse --short HEAD)
DIR=emacs-$DATE-$SHORT
git archive --prefix="$DIR/" HEAD | tar x
(cd $DIR && ./autogen.sh)
tar cjf $DIR.tar.bz2 $DIR

Emacs Dependencies

By default build-emacs-from-tar will attempt to gather several extra dependencies to make Emacs more full featured. You can disable this with the --no-deps option. There are 2 ways the dependencies can be built:

1. By downloading prebuilt packages using Nix. If you have installed Nix on your Mac, then build-emacs-from-tar should autodetect this and use nix-shell (which must be in your PATH) to install a list of dependencies. The dependency list can be found in dependencies.nix.

2. By downloading and compiling a list programs. This happens if Nix is not installed. The list is canned and can be found in build-dependencies.rb. This method is not used any more by the builds on emacsformacosx.com as it is prone to getting out of date and requires a lot of up-keep. The code to do this (build.rb) will be removed at some point.

No matter which method is used, build-emacs-from-tar modifies the dependencies' libraries as it copies them into Emacs.app so that the app bundle remains portable.

The Rust launcher

To compile the Rust launcher (needed by combine-and-package):

make

combine-and-package

This takes multiple tar files as input, unpacks and combines them into a final "fat" Emacs.app, then creates a final disk image (.dmg). It takes an optional --sign parameter (--sign="my identity") which makes it code sign the Emacs.app.

Example

$ ./fetch-emacs-from-ftp -v ftp://ftp.gnu.org/pub/gnu/emacs
+ curl --continue-at - --silent -O ftp://ftp.gnu.org/pub/gnu/emacs/emacs-25.1.tar.xz
shell(#<Th:0x007febed8a48b0>): /usr/local//brew//bin/xzcat emacs-25.1.tar.xz
shell(#<Th:0x007febed8a48b0>): /usr/bin/bzip2
$ ls *.bz2
emacs-25.1.tar.bz2
$ ./build-emacs-from-tar -v -j 8 emacs-25.1.tar.bz2 release
  ... Lots out output snipped ...
Built Emacs-25.1-10.12-x86_64.tar.bz2, Emacs-25.1-10.12-x86_64-extra-source.tar
$ ./combine-and-package -v Emacs-25.1-10.12-x86_64.tar.bz2
  ... More output snipped ...
created: Emacs-25.1-universal.dmg

License

Copyright © 2004-2024 David Caldwell david@porkrind.org

The scripts and programs contained in this distribution are licensed under the GNU General Public License (v3.0). See the LICENSE file for details.