A helper script to build Emacs from source on Debian/Ubuntu

build-emacs.sh

#!/bin/bash
# -*- sh-basic-offset: 2; tab-width: 2; -*-

# set -x

# Initially based on the emacs-git AUR package

## Build options

USE_CLANG=                   # Use Clang instead of GCC.
LINK_TIME_OPTIMIZATION="YES" # Enable link-time optimization.
AOT_ELISP=                   # Compile all elisp files provided by upstream.
MAKE_TRAMPOLINES=            # Compile jitted Elisp files with trampolines.
ALSA=                        # Linux sound support.
MAKE_DOCS_HTML=              # Generate and install html documentation.
MAKE_DOCS_PDF=               # Generate and install pdf documentation. You need a TeX installation.
EMACS_BRANCH="emacs-30"      # Emacs' branch to be built.
UI="GTK3"                    # GTK3, PGTK, LUCID
XWIDGETS=                    # XWidgets support
PERFORMANCE_TWEAKS="YES"     # Apply some performance related tweaks

# ===================================================================

emacs_system_make_depends=(
  'git'
  'gcc'
  'autoconf'
)

# Maybe not complete list
debian_system_depends=(
  'libgnutls28-dev' 'libxml2-dev' 'libharfbuzz-dev' 'texinfo' 'libxi-dev'
  'libjpeg-dev' 'libpng-dev' 'giflib-tools' 'libgif-dev' 'libwebp-dev' 'libtiff-dev' 'libxpm-dev'
  'libjansson-dev'   # Native JSON support for Emacs 29, not needed for 30+
  'libgccjit-12-dev' # Native compile (28+)
  'tree-sitter-dev'  # Treesitter (29+)
  'libsqlite3-dev'   # SQLite
  'libgpm-dev'       # GPM
  'libcairo2-dev'    # Cairo
)

src_dir=$PWD/emacs

# ===================================================================

if [[ "${USE_CLANG}" == "YES" ]]; then
  export CC="/usr/bin/clang"
  export CXX="/usr/bin/clang++"
  export CPP="/usr/bin/clang -E"
  export LD="/usr/bin/lld"
  export AR="/usr/bin/llvm-ar"
  export AS="/usr/bin/llvm-as"
  export CCFLAGS+=' -fuse-ld=lld'
  export CXXFLAGS+=' -fuse-ld=lld'
  system_make_depends+=('clang' 'lld' 'llvm')
fi

if [[ "${UI}" == "LUCID" ]]; then
  system_depends+=('dbus' 'hicolor-icon-theme' 'libxinerama-dev' 'libxfixes-dev' 'librsvg2-dev' 'xaw3dg-dev' 'libxrandr-dev' 'libxi-dev' 'libsm-dev' 'xcb' 'libxcb1-dev')
  system_make_depends+=('x11proto-dev')
elif [[ "${UI}" == "GTK3" ]]; then
  system_depends+=('libgtk-3-dev' 'libsm-dev' 'xcb' 'libxcb1-dev')
  system_make_depends+=('x11proto-dev' 'libxi-dev')
elif [[ "${UI}" == "PGTK" ]]; then
  system_depends+=('libgtk-3-dev' 'libsm-dev' 'xcb' 'libxcb1-dev')
  system_make_depends+=('x11proto-dev' 'libxi-dev')
fi

if [[ "${XWIDGETS}" == "YES" ]]; then
  system_make_depends+=('libwebkit2gtk-4.0-dev')
fi

if [[ "${ALSA}" == "YES" ]]; then
  system_depends+=('alsa-lib')
fi

if [[ "${MAKE_DOCS_PDF}" == "YES" ]] && [[ ! -d '/usr/local/texlive' ]]; then
  system_make_depends+=('texlive-core')
fi

emacs-install-dependencies() {
  apt install "${debian_system_depends[@]}" "${emacs_system_make_depends[@]}"
}

proxy-enable() {
  if ping -c3 -W2 1.1.1.1 | grep -q "0 received"; then
    echo "Cannot ping WAN, setting proxies"
    export https_proxy=http://SOME_LOCAL_PROXY:8080/
    export http_proxy=http://SOME_LOCAL_PROXY:8080/
    export ftp_proxy=http://SOME_LOCAL_PROXY:8080/
    export no_proxy=localhost,127.0.0.1,.local,.SOME_LOCAL_TLD
  fi
}

# There is no need to run autogen.sh after first checkout.
# Doing so, breaks incremental compilation.
emacs-prepare() {
  # proxy-enable

  if [[ ! -d "${src_dir}" ]]; then
    git clone https://github.com/emacs-mirror/emacs.git "${src_dir}" -b "${EMACS_BRANCH}"
  else
    cd "${src_dir}" || exit 1
    git stash --include-untracked
    git pull origin
    git checkout "${EMACS_BRANCH}"
  fi

  [[ -d "${src_dir}/build" ]] && rm -rf "${src_dir}/build"
  [[ -x configure ]] || (./autogen.sh git && ./autogen.sh autoconf)
  mkdir -p "${src_dir}/build"
}

emacs-check() {
  cd "${src_dir}/build" || exit 1
  make check
}

emacs-build() {
  cd "${src_dir}/build" || exit 1

  if [[ "${PERFORMANCE_TWEAKS}" == "YES" ]]; then
    # This disables the GC mark trace buffer for about 5% better garbage collection performance
    config_options+=('--disable-gc-mark-trace')

    # Better compilation optimization
    export CFLAGS+="-O2 -pipe -march=native -mtune=native -fomit-frame-pointer"
  fi

  local config_options=(
    --prefix="$HOME/.local"
    --sysconfdir=/etc
    --libexecdir="$HOME/.local/lib"
    --localstatedir="$HOME/.local/var"
    --mandir="$HOME/.local/share/man"
    --with-gnutls=ifavailable
    --with-tree-sitter=ifavailable
    --with-native-compilation # No need for this on Emacs 30, it is the default if libgccjit is available
    --with-xinput2
    --without-compress-install
    --with-modules
    --without-libotf
    --without-m17n-flt
    # Beware https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25228
    # dconf and gconf break font settings you set in ~/.emacs.
    # If you insist you'll need to read that bug report in *full*.
    # Good luck!
    --without-gconf
    # ctags/etags may be provided by other packages, e.g, universal-ctags
    --program-transform-name='s/\([ec]tags\)/\1.emacs/'
  )

  if [[ "${USE_CLANG}" == "YES" ]]; then
    config_options+=('--enable-autodepend')
  fi

  if [[ "${LINK_TIME_OPTIMIZATION}" == "YES" ]]; then
    config_options+=('--enable-link-time-optimization')
  fi

  if [[ "${AOT_ELISP}" == "YES" ]]; then
    config_options+=('--with-native-compilation=aot')
  fi

  if [[ "${UI}" == "LUCID" ]]; then
    config_options+=('--with-x-toolkit=lucid' '--with-xft' '--with-xaw3d' '--without-cairo')
  elif [[ "${UI}" == "GTK3" ]]; then
    config_options+=('--with-x-toolkit=gtk3' '--without-xaw3d')
  elif [[ "${UI}" == "PGTK" ]]; then
    config_options+=('--with-pgtk' '--without-xaw3d' '--without-gsettings')
  fi

  if [[ "${XWIDGETS}" == "YES" ]]; then
    config_options+=('--with-xwidgets')
  fi

  if [[ "${ALSA}" == "YES" ]]; then
    config_options+=('--with-sound=alsa')
  else
    config_options+=('--with-sound=no')
  fi

  # ===================================================================

  ../configure "${config_options[@]}"

  make bootstrap

  # -------------------------------------------------------------------
  # Or use "make" rather than "make bootstrap":

  # > make

  # Using "make" instead of "make bootstrap" enables incremental
  # compiling. Less time recompiling. Yay! But you may
  # need to use bootstrap sometimes to unbreak the build.
  # Just add it to the command line.
  #
  # Please note that incremental compilation implies that you
  # are reusing your src directory!
  #

  # You may need to run this if 'loaddefs.el' files become corrupt.
  # cd "${src_dir}/lisp"
  # make autoloads
  # cd ../build
  # -------------------------------------------------------------------

  if [[ "${MAKE_TRAMPOLINES}" == "YES" ]]; then
    make trampolines
  fi

  # Optional documentation formats.
  if [[ "${MAKE_DOCS_HTML}" == "YES" ]]; then
    make html
  fi

  if [[ "${MAKE_DOCS_PDF}" == "YES" ]]; then
    make pdf
  fi
}

emacs-install() {
  cd "${src_dir}/build" || exit 1

  make PREFIX="${HOME}/.local/" install

  # Install Emacs terminal command
  if [[ ! -f "${HOME}/.local/bin/nemacs" ]]; then
    printf '#!/usr/bin/bash -e\n\n[[ -x $HOME/.local/bin/emacs ]] && $HOME/.local/bin/emacs -nw $*' >"${HOME}/.local/bin/nemacs"
    chmod a+x "${HOME}/.local/bin/nemacs"
  fi

  # Install optional documentation formats
  if [[ $MAKE_DOCS_HTML == "YES" ]]; then make PREFIX="${HOME}/.local/" install-html; fi
  if [[ $MAKE_DOCS_PDF == "YES" ]]; then make PREFIX="${HOME}/.local/" install-pdf; fi
}

emacs-build-and-install() {
  echo "Preparing the build"
  emacs-prepare
  echo "Building Emacs"
  emacs-build
  echo "Installing Emacs"
  emacs-install
}

emacs-build-and-install