This script automates the process of compiling GNU Emacs on the MS Windows platform. Multiple toolchains(Msys2, MinGW, Cygwin) are supported.
- Git. It should be present on your PATH.
- Wget. You can get it from GnuWin project. Or from ezwinports. Then either put it on PATH or set mwb-wget-paths. The default path for the GnuWin version is already set up.
Anything downloaded by this script using wget gets stored inside mwb-wget-download-directory and reused if it’s already there.
Bsdtar would get installed, unless it’s already present on your PATH. If it’s not present unzip.exe would be downloaded and used to install it.
Any toolchain required would be installed and set up for building Emacs, unless already present.
Put the script onto your load-path, then require it:
(require 'ms-windows-builder)Then call the build function:
(mwb-build selected-toolchain output-directory configuration source)Toolchain should be a symbol pointing to one of the toolchains defined in mwb-toolchains.
Output directory is the directory into which Emacs would get installed.
Configuration is optional and should be a symbol pointing to one of the configurations preset in mwb-configurations. By default mwb-default-configuration is used.
Source should be pointing to a folder containing GNU Emacs sources. Or you can set mwb-emacs-source instead.
Example usage:
;; Call only one of those at a time, not all!
(mwb-build 'mingw "c:/Emacs/bin/main-release-mingw" 'release "c:/Emacs/source/repo")
(mwb-build 'msys2-x32 "c:/Emacs/bin/main-release-msys2-x32" 'release "c:/Emacs/source/repo")
(mwb-build 'msys2-x64 "c:/Emacs/bin/main-release-msys2-x64" 'release "c:/Emacs/source/repo")
(mwb-build 'cygwin-x32 "c:/Emacs/bin/main-release-cygwin-x32" 'release "c:/Emacs/source/repo")
(mwb-build 'cygwin-x64 "c:/Emacs/bin/main-release-cygwin-x64" 'release "c:/Emacs/source/repo")
;; Configuration and source are actually optional.
(mwb-build 'msys2-x64 "c:/Emacs/bin/main-release-msys2-x64")This script outputs everything into the “mwb” buffer. You can stop the build process at any time by calling mwb-stop.
Depending on your hardware and whether you are installing the toolchain, the whole process is estimated to take between 10 and 30 minutes.
You can use mwb-finish-notification-functions hook to pass build completion notifications. For example, you can use notify-send for Windows to send messages into Windows 10 notification center:
(defun mwb-notify-send (message)
(call-process-shell-command (format "notify-send MWB \"%s\"" message)))
(add-hook 'mwb-finish-notification-functions 'mwb-notify-send)During msys2 setup you would get a shell window. You can close it after it’s done with the setup and you see the command prompt.
Cygwin provides a run.exe utility you can use to start Emacs:
c:\cygwin64\bin\run.exe emacs-27.1.exe
To ensure that everything possible is working in your Emacs build, you should check for the presence of the following features.
Evaluating (sqlite-available-p) should return a non-nil value. Sqlite is supported since Emacs 29.1.
Evaluating (frame-parameter nil 'font-backend) should return harfbuzz first. Emacs is using harfbuzz since 27.1.
Evaluating (gnutls-available-p) should return a non-nil value.
Since Emacs 27.1 you can eval (libxml-available-p) and it should return t. For older versions the code bellow should return (xml nil):
(with-temp-buffer (insert "<xml></xml>") (libxml-parse-xml-region (point-min) (point-max)))Evaluating (json-serialize '((test . 1))) should return a non-nil value. Json library support was added in 27.1.
GMP should be one of the values in system-configuraiton-features. GMP is supported since 27.1.
Make sure to try and open all 6 supported image formats.
Harfbuzz and GMP currently does not work for MinGW.
If you have MinGW already installed and try to use the same location, but it does not have all of the required components, the build would break. You can manually install components into an existing directory using (mwb-mingw-install-packages). This script assumes that your Msys is installed within the MinGW tree. Otherwise, installing a different MinGW using this script is highly recommended.
Cygwin no longer officially suports 32 bit architecture, so the last working snapshot is used for 32 bit builds.
Cygwin builds are done --with-w32, harfbuzz does not work and there is no svg image support.
The build would break if you have Cygwin already installed and try to use the same location, but it does not have all of the required components. You can manually install packages into an existing Cygwin installation by evaluating (mwb-cygwin-install 'x32) for x32 and (mwb-cygwin-install 'x64) for x64.
Make sure that mwb-wget-download-directory, mwb-configurations-directory, the toolchain directory you want to use(mwb-mingw-directory, mwb-msys2-64-directory, mwb-msys2-32-directory) and the root of your output-directory are all writable. For the output directory we want the root, since we’re actually compiling into a temporary directory first and then renaming it.
If the script is unable to download one of the dependenices, open its path in browser and see if there’s a newer version. Then replace it in the config file.
If some optional feature does not work, try opening the library dll with the Dependencies to see if it has some new dependency you’re missing and try copying that dependency into your emacs/bin folder. It’s probably librsvg and it just won’t stop until it starts depending on every single library ever written.
For Msys2 it should install all of the required packages, you can also force the package installation manually using (mwb-msys2-install-packages).
This script was tested for each toolchain building the following Emacs versions. The latest versions are installed for most of the toolchain components, so you can expect this info to be wrong due to possible future versions breaking the builds. Only the MinGW toolchain is strictly tied to the particular component versions, so the compatibility for it should not change.
For this and older you need to add LDFLAGS=-Wl,--disable-dynamicbase,--disable-high-entropy-va,--default-image-base-low into mwb-configurations configure-env for a 64 bit build and LDFLAGS=-Wl,--disable-dynamicbase for 32 bit. This is due to msys2 enabling ASLR by default since binutils 2.36 and this breaks Emacs unexec. Alternatively you can downgrade binutils to 2.35 or older.
Msys2 now reports a host system incompatible with the 24.5 sources. Hence you need to patch configure.ac file, replacing “mingw32” with “mingw*” on lines 625 and 1264.
Furthermore you need to add -D_FORTIFY_SOURCE=0 to CFLAGS for the appropriate configuration in mwb-configurations.
If you are using a configuration with optimization enabled, make sure you set instal-strip to nil, because stripping breaks binaries for this version.
For a 32 bit build make sure you remove --with-wide-int from your configuration.
For this and older you need to enable the use of the older, sourceforge-only, MinGW distribution in the config file.
For this version and older you need to enable the use of the older dependencies in the config file.
When building this and older remove --with-wide-int from the configuration you’re using in mwb-configurations. You also should not use any configuration that combines optimization(-O > 0) and debug info(-gdwarfX, -gX), since this results in corrupted binaries.
When building this and older you need to use an old Cygwin snapshot from Cygwin Time Machine.
For 64 bit build:
(setq mwb-cygwin-install-extra-args '("-X")
mwb-cygwin-site "http://ctm.crouchingtigerhiddenfruitbat.org/pub/cygwin/circa/64bit/2016/02/18/234032")For 32 bit build:
(setq mwb-cygwin-install-extra-args '("-X")
mwb-cygwin-site "http://ctm.crouchingtigerhiddenfruitbat.org/pub/cygwin/circa/2016/02/19/144014")Cygwin snapshots newer than 2016-04-10 are not compatible with the Glib version used by Emacs 24. Snapshots newer than 2016-02-19 fail during Emacs bootstrap.
On top of that you need to patch src/profiler.c around line 220 by adding:
/* timer_getoverrun is not implemented on Cygwin, but the following
seems to be good enough for profiling. */
#ifdef CYGWIN
#define timer_getoverrun(x) 0
#endif