Build Emacs with MSYS2

This document is an up-to-date guide on compile Emacs 31 on windows with MSYS2, and make a installation with native compile that can work without MSYS2.

The idea is after get a working Emacs, you may delete MSYS2 environment to free some disk space, and forget about rebuilding Emacs until the next time you feel need to, without need to figure out everything again.

Specially thanks to @include-yy on emacs-china.org for providing guides on UCRT64 and use GCCJIT.

How to get MSYS2 (without installer)

Get from https://github.com/msys2/msys2-installer/releases/

You may use the 7zip SFX one.

Update MSYS2 base environment

We are using the UCRT64.

pacman -Syu

After complete, restart terminal, and run

pacman -Su

To install the required packages for building Emacs. (Maybe other people can came up with a better list)

pacman -Su \
  autoconf \
  autogen \
  automake \
  automake-wrapper \
  git \
  libidn-devel \
  libltdl \
  libnettle-devel \
  libopenssl \
  libp11-kit-devel \
  libtasn1-devel \
  libunistring \
  make \
  mingw-w64-ucrt-x86_64-toolchain \
  mingw-w64-ucrt-x86_64-bzip2 \
  mingw-w64-ucrt-x86_64-cairo \
  mingw-w64-ucrt-x86_64-crt-git \
  mingw-w64-ucrt-x86_64-expat \
  mingw-w64-ucrt-x86_64-fontconfig \
  mingw-w64-ucrt-x86_64-freetype \
  mingw-w64-ucrt-x86_64-gcc \
  mingw-w64-ucrt-x86_64-gcc-libs \
  mingw-w64-ucrt-x86_64-gdk-pixbuf2 \
  mingw-w64-ucrt-x86_64-gettext \
  mingw-w64-ucrt-x86_64-giflib \
  mingw-w64-ucrt-x86_64-glib2 \
  mingw-w64-ucrt-x86_64-gmp \
  mingw-w64-ucrt-x86_64-gnutls \
  mingw-w64-ucrt-x86_64-harfbuzz \
  mingw-w64-ucrt-x86_64-headers-git \
  mingw-w64-ucrt-x86_64-imagemagick \
  mingw-w64-ucrt-x86_64-jansson \
  mingw-w64-ucrt-x86_64-libgccjit \
  mingw-w64-ucrt-x86_64-libiconv \
  mingw-w64-ucrt-x86_64-libidn2 \
  mingw-w64-ucrt-x86_64-libjpeg-turbo \
  mingw-w64-ucrt-x86_64-libpng \
  mingw-w64-ucrt-x86_64-librsvg \
  mingw-w64-ucrt-x86_64-sqlite3 \
  mingw-w64-ucrt-x86_64-tree-sitter
  mingw-w64-ucrt-x86_64-libtiff \
  mingw-w64-ucrt-x86_64-libunistring \
  mingw-w64-ucrt-x86_64-libxml2 \
  mingw-w64-ucrt-x86_64-nettle \
  mingw-w64-ucrt-x86_64-p11-kit \
  mingw-w64-ucrt-x86_64-winpthreads \
  mingw-w64-ucrt-x86_64-xpm-nox \
  mingw-w64-ucrt-x86_64-xz \
  mingw-w64-ucrt-x86_64-zlib \
  mingw-w64-ucrt-x86_64-jbigkit \
  pkgconf \
  texinfo \

Fetch Emacs source

git config --global core.autocrlf false
git clone https://github.com/emacs-mirror/emacs --depth 1

Build Emacs

It is recommended to disable Windows Defender scan for MSYS2 or use Window 11 Dev Drive feature to speed up compilation.

Configuration

It is important to --with-gnutls, because otherwise Emacs won’t even able to use ELPA outside MSYS2. Also, dbus is not useful for Emacs on Windows. You may change other flags as you see appropriate.

Set prefix to somewhere appropriate.

cd emacs
./autogen.sh
mkdir build
cd build
target=/g/emacs
../configure prefix=$target \
    --with-native-compilation=aot \
    --with-gnutls \
    --without-dbus \
    --without-pop \
    --with-xpm \
    --with-imagemagick \
    --with-tree-sitter

Check if the configure log is appropriate.

Building Emacs

Then make bootstrap it (for develop branch). After building completes, make install and open the $target directory.

Post building

DLL Hell

The easiest way is to copy all the dlls from /ucrt64/bin, and exploit the property that Windows won’t allow delete currently opened files to trim it. Still that doesn’t mean all the successfully deleted DLLs are safe to purge. Before you hit “Clean Recycle Bin”, tt is a good idea to check against the Windows binary distributed by GNU for DLL used by Emacs.

The good things is, even if you have found certain DLL is missing afterwards, you can still download the individual package without reinstall MSYS2.

XPM image

This requires libXpm-noX4.dll. Emacs can start without this DLL but then it won’t be able to display XPM image.

Treesitter

libtree-sitter.dll depends on wasmtime.dll.

GCCJIT

Additional works are required to make native compile work without complete MSYS2 environment.

mkdir $target/lib/gcc
cp /ucrt64/lib/{crtbegin,crtend,dllcrt2}.o $target/lib/gcc
cp /ucrt64/lib/lib{advapi32,gcc_s,mingw32,msvcrt,shell32,kernel32,mingwex,pthread,user32}.a $target/lib/gcc
# adjust path according to gcc version
cp /ucrt64/lib/gcc/x86_64-w64-mingw32/14.2.0/libgcc.a $target/lib/gcc
cp /ucrt64/bin/{ld,as}.exe $target/lib/gcc

LdBeth/build.org