bootstrap - autoconf - Git at Google

 #! /bin/sh

 # This script helps bootstrap autoconf, when checked out from git.
 #
 # Copyright (C) 2021-2025 Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2, or (at your option)
 # any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.

 # Autoconf's own configure script is generated using Autoconf.  This
 # script does what running `autoreconf -i` in an Autoconf git checkout
 # would do, except that it uses autoconf from the source tree we are
 # preparing, not any version of autoconf that might or might not be
 # installed already.  Note that automake, Perl, and GNU M4 _are_
 # required to be installed already.

 # Don't ignore failures.
 set -e
 (set -o pipefail 2> /dev/null) && set -o pipefail

 # Error on undefined variables.
 (set -u 2> /dev/null) && set -u

 # Avoid problems due to various shell wrinkles.
 # We assume we have a shell new enough to implement unset correctly.
 (set -o posix 2> /dev/null) && set -o posix

 PS1='$ '
 PS2='> '
 PS4='+ '
 unset BASH_ENV CDPATH ENV IFS MAIL MAILPATH POSIXLY_CORRECT
 unset LANG LANGUAGE LC_ADDRESS LC_COLLATE LC_CTYPE LC_IDENTIFICATION
 unset LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER
 unset LC_TELEPHONE LC_TIME

 LC_ALL=C
 export LC_ALL

 # Set program basename.
 me=${0##*/}
 usage="usage: $me [options]

 Prepare to build a git checkout of autoconf.
 Functionally equivalent to \`autoreconf -i\`, but uses autoconf code
 from the git checkout itself to create \`configure\`.

 Options:
   -f, --force      consider all files to be obsolete
   -v, --verbose    verbosely report processing (repeat for more detail)
 "

 # Options.
 verbose=
 subverbose=
 force=
 while [ $# -gt 0 ]; do
     case "$1" in
         (-v | --verbose)
             if [ -n "$verbose" ]; then
                 subverbose=--verbose
             else
                 verbose=--verbose
             fi
         ;;
         (-f | --force)
             force=--force
         ;;
         (-h | --help)
             printf '%s' "$usage"
             exit 0
         ;;
         (*)
             printf '%s' "$usage" >&2
             exit 1
         ;;
     esac
     shift
 done


 # Let the user choose which version of aclocal, automake, m4, and perl to use.
 : ${ACLOCAL=aclocal}
 : ${AUTOMAKE=automake}
 : ${M4=m4}
 : ${PERL=perl}
 export ACLOCAL AUTOMAKE M4 PERL

 # Allow 'ln -s' to be overridden by the user.
 : ${LN_S="ln -s"}
 export LN_S

 # $PERL needs to be an absolute path because we're going to substitute it
 # into #! lines.
 set fnord $PERL
 shift
 PERL=$(command -v $1)
 shift
 if [ $# -gt 0 ]; then
     PERL="$PERL $*"
 fi

 # Override SHELL.  This is required on DJGPP so that Perl's system()
 # uses bash, not COMMAND.COM which doesn't quote arguments properly.
 # It's not used otherwise.
 if test -n "${DJDIR-}"; then
   BOOTSTRAP_SHELL=/dev/env/DJDIR/bin/bash.exe
 else
   BOOTSTRAP_SHELL=/bin/sh
 fi

 # Determine whether we have a usable version of M4.
 # This rule is pickier than the rule in autoconf's actual configure script.
 m4_version="$($M4 --version | head -1)"
 case "$m4_version" in
   ( *\ 0.*                \
   | *\ 1.[0123]           \
   | *\ 1.[0123].*         \
   | *\ 1.4.[0123456789]   \
   | *\ 1.4.1[012345]      \
   )
     printf '%s\n' "$me: $M4 ($m4_version) is too old" >&2
     exit 1
     ;;
 esac

 # Substitutions related to the version of M4 available.
 M4_DEBUGFILE=
 M4_GNU=
 m4_help=$($M4 --help)
 case "$m4_help" in
   (*--debugfile*)
     M4_DEBUGFILE=--debugfile ;;
   (*--error-output*)
     M4_DEBUGFILE=--error-output ;;
 esac
 case "$m4_help" in
   (*--gnu*)
     M4_GNU=--gnu ;;
 esac

 # Autoconf's version number and identifiers.
 RELEASE_YEAR=$(sed -ne 's/^RELEASE_YEAR=\([0-9][0-9]*\)$/\1/p' configure.ac)
 VERSION=$(build-aux/git-version-gen .tarball-version)

 # PACKAGE_NAME and PACKAGE_BUGREPORT from the bootstrap autoconf can
 # get copied into the generated configure script, so we need to get them
 # right.  Caution: there is a hard tab in one of the regexes below.
 PACKAGE_NAME=$(sed -n < configure.ac \
    -e 's/^m4_define(\[autoconf_PACKAGE_NAME], \[\([^]]*\)])$/\1/p')
 PACKAGE_BUGREPORT=$(sed -n < configure.ac \
    -e 's/^m4_define(\[autoconf_PACKAGE_BUGREPORT], \[\([^]]*\)])$/\1/p')

 if [ -z "$RELEASE_YEAR" ]; then
     printf >&2 '%s\n' \
       "$me: error: could not extract RELEASE_YEAR from configure.ac"
     exit 1
 fi
 if [ -z "$VERSION" ]; then
     printf >&2 '%s\n' "$me: error: could not compute VERSION"
     exit 1
 fi
 if [ -z "$PACKAGE_NAME" ]; then
     printf >&2 '%s\n' \
       "$me: error: could not extract PACKAGE_NAME from configure.ac"
     exit 1
 fi
 if [ -z "$PACKAGE_BUGREPORT" ]; then
     printf >&2 '%s\n' \
       "$me: error: could not extract PACKAGE_BUGREPORT from configure.ac"
     exit 1
 fi

 # PACKAGE_TARNAME and PACKAGE_URL from the bootstrap autoconf should not
 # get copied into the configure script.
 PACKAGE_URL='<<not available>>'
 PACKAGE_TARNAME='<<not available>>'

 # Root for temporary partial installation tree.
 ACBOOTDIR=$(mktemp -d acboot.XXXXXXXXXX)
 ACBOOTDIR=$(realpath $ACBOOTDIR)

 # dosubst options infile outfile -- performs the substitutions that
 # config.status would perform on INFILE, creating OUTFILE.  INFILE is
 # relative to the source directory, OUTFILE is relative to $ACBOOTDIR.
 # If OPTIONS is the letter 'x', OUTFILE is made executable after creation.
 dosubst ()
 {
     in=${2##*/}
     out="$ACBOOTDIR/$3"
     if [ -n "$verbose" ]; then
         printf '%s: creating %s\n' "$me" "$out"
     fi
     rm -f "$out"
     sed -e "s%@configure_input@%Generated from $in; do not edit by hand.%g" \
         -e "s%@M4@%$M4%g" \
         -e "s%@M4_DEBUGFILE@%$M4_DEBUGFILE%g" \
         -e "s%@M4_GNU@%$M4_GNU%g" \
         -e "s%@PACKAGE_BUGREPORT@%$PACKAGE_BUGREPORT%g" \
         -e "s%@PACKAGE_NAME@%$PACKAGE_NAME%g" \
         -e "s%@PACKAGE_STRING@%$PACKAGE_NAME $VERSION%g" \
         -e "s%@PACKAGE_TARNAME@%$PACKAGE_TARNAME%g" \
         -e "s%@PACKAGE_URL@%$PACKAGE_URL%g" \
         -e "s%@PACKAGE_VERSION@%$VERSION%g" \
         -e "s%@PERL@%$PERL%g" \
         -e "s%@PERL_FLOCK@%0%g" \
         -e "s%@RELEASE_YEAR@%$RELEASE_YEAR%g" \
         -e "s%@SHELL@%$BOOTSTRAP_SHELL%g" \
         -e "s%@VERSION@%$VERSION%g" \
         -e "s%@pkgdatadir@%$ACBOOTDIR/lib%g" \
         "$2" > "$out"
     if [ "$1" = "x" ]; then
         chmod +x "$out"
     fi
 }

 # Create the bootstrap installation.
 mkdir "$ACBOOTDIR"/bin "$ACBOOTDIR"/lib "$ACBOOTDIR"/tmp
 (
     cd "$ACBOOTDIR"/lib
     for sub in Autom4te autoconf m4sugar ; do
         if [ -n "$verbose" ]; then
             printf '%s: creating %s\n' "$me" "$ACBOOTDIR/lib/$sub"
         fi
         $LN_S ../../lib/$sub .
     done
 )

 # automake invokes autoconf, and autoconf and aclocal both invoke autom4te,
 # so we need to create both of them.
 dosubst x bin/autoconf.in bin/autoconf
 dosubst x bin/autom4te.in bin/autom4te
 dosubst . lib/autom4te.in lib/autom4te.cfg
 dosubst . lib/version.in  lib/version.m4

 AUTOCONF="$ACBOOTDIR"/bin/autoconf
 AUTOM4TE="$ACBOOTDIR/bin/autom4te -M -C $ACBOOTDIR/tmp/autom4te.cache"
 export AUTOCONF AUTOM4TE

 # We can now do what autoreconf would have done.
 # Order is critical -- first aclocal, then autoconf, then automake.
 run ()
 {
     if [ -n "$verbose" ]; then
         printf '%s: running %s\n' "$me" "$*"
     fi
     "$@"
 }

 run $ACLOCAL -I m4 -Wall -Werror $subverbose $force
 run $AUTOCONF -Wall -Werror $subverbose $force
 run $AUTOMAKE --add-missing --copy -Wall -Werror $subverbose $force

 # Clean up.
 rm -rf "$ACBOOTDIR"
	#! /bin/sh

	# This script helps bootstrap autoconf, when checked out from git.
	#
	# Copyright (C) 2021-2025 Free Software Foundation, Inc.
	#
	# This program is free software; you can redistribute it and/or modify
	# it under the terms of the GNU General Public License as published by
	# the Free Software Foundation; either version 2, or (at your option)
	# any later version.
	#
	# This program is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	# GNU General Public License for more details.
	#
	# You should have received a copy of the GNU General Public License
	# along with this program. If not, see <https://www.gnu.org/licenses/>.

	# Autoconf's own configure script is generated using Autoconf. This
	# script does what running `autoreconf -i` in an Autoconf git checkout
	# would do, except that it uses autoconf from the source tree we are
	# preparing, not any version of autoconf that might or might not be
	# installed already. Note that automake, Perl, and GNU M4 _are_
	# required to be installed already.

	# Don't ignore failures.
	set -e
	(set -o pipefail 2> /dev/null) && set -o pipefail

	# Error on undefined variables.
	(set -u 2> /dev/null) && set -u

	# Avoid problems due to various shell wrinkles.
	# We assume we have a shell new enough to implement unset correctly.
	(set -o posix 2> /dev/null) && set -o posix

	PS1='$ '
	PS2='> '
	PS4='+ '
	unset BASH_ENV CDPATH ENV IFS MAIL MAILPATH POSIXLY_CORRECT
	unset LANG LANGUAGE LC_ADDRESS LC_COLLATE LC_CTYPE LC_IDENTIFICATION
	unset LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER
	unset LC_TELEPHONE LC_TIME

	LC_ALL=C
	export LC_ALL

	# Set program basename.
	me=${0##*/}
	usage="usage: $me [options]

	Prepare to build a git checkout of autoconf.
	Functionally equivalent to \`autoreconf -i\`, but uses autoconf code
	from the git checkout itself to create \`configure\`.

	Options:
	-f, --force consider all files to be obsolete
	-v, --verbose verbosely report processing (repeat for more detail)
	"

	# Options.
	verbose=
	subverbose=
	force=
	while [ $# -gt 0 ]; do
	case "$1" in
	(-v \| --verbose)
	if [ -n "$verbose" ]; then
	subverbose=--verbose
	else
	verbose=--verbose
	fi
	;;
	(-f \| --force)
	force=--force
	;;
	(-h \| --help)
	printf '%s' "$usage"
	exit 0
	;;
	(*)
	printf '%s' "$usage" >&2
	exit 1
	;;
	esac
	shift
	done


	# Let the user choose which version of aclocal, automake, m4, and perl to use.
	: ${ACLOCAL=aclocal}
	: ${AUTOMAKE=automake}
	: ${M4=m4}
	: ${PERL=perl}
	export ACLOCAL AUTOMAKE M4 PERL

	# Allow 'ln -s' to be overridden by the user.
	: ${LN_S="ln -s"}
	export LN_S

	# $PERL needs to be an absolute path because we're going to substitute it
	# into #! lines.
	set fnord $PERL
	shift
	PERL=$(command -v $1)
	shift
	if [ $# -gt 0 ]; then
	PERL="$PERL $*"
	fi

	# Override SHELL. This is required on DJGPP so that Perl's system()
	# uses bash, not COMMAND.COM which doesn't quote arguments properly.
	# It's not used otherwise.
	if test -n "${DJDIR-}"; then
	BOOTSTRAP_SHELL=/dev/env/DJDIR/bin/bash.exe
	else
	BOOTSTRAP_SHELL=/bin/sh
	fi

	# Determine whether we have a usable version of M4.
	# This rule is pickier than the rule in autoconf's actual configure script.
	m4_version="$($M4 --version \| head -1)"
	case "$m4_version" in
	( \ 0. \
	\| *\ 1.[0123] \
	\| \ 1.[0123]. \
	\| *\ 1.4.[0123456789] \
	\| *\ 1.4.1[012345] \
	)
	printf '%s\n' "$me: $M4 ($m4_version) is too old" >&2
	exit 1
	;;
	esac

	# Substitutions related to the version of M4 available.
	M4_DEBUGFILE=
	M4_GNU=
	m4_help=$($M4 --help)
	case "$m4_help" in
	(--debugfile)
	M4_DEBUGFILE=--debugfile ;;
	(--error-output)
	M4_DEBUGFILE=--error-output ;;
	esac
	case "$m4_help" in
	(--gnu)
	M4_GNU=--gnu ;;
	esac

	# Autoconf's version number and identifiers.
	RELEASE_YEAR=$(sed -ne 's/^RELEASE_YEAR=\([0-9][0-9]*\)$/\1/p' configure.ac)
	VERSION=$(build-aux/git-version-gen .tarball-version)

	# PACKAGE_NAME and PACKAGE_BUGREPORT from the bootstrap autoconf can
	# get copied into the generated configure script, so we need to get them
	# right. Caution: there is a hard tab in one of the regexes below.
	PACKAGE_NAME=$(sed -n < configure.ac \
	-e 's/^m4_define(\[autoconf_PACKAGE_NAME], \[\([^]]*\)])$/\1/p')
	PACKAGE_BUGREPORT=$(sed -n < configure.ac \
	-e 's/^m4_define(\[autoconf_PACKAGE_BUGREPORT], \[\([^]]*\)])$/\1/p')

	if [ -z "$RELEASE_YEAR" ]; then
	printf >&2 '%s\n' \
	"$me: error: could not extract RELEASE_YEAR from configure.ac"
	exit 1
	fi
	if [ -z "$VERSION" ]; then
	printf >&2 '%s\n' "$me: error: could not compute VERSION"
	exit 1
	fi
	if [ -z "$PACKAGE_NAME" ]; then
	printf >&2 '%s\n' \
	"$me: error: could not extract PACKAGE_NAME from configure.ac"
	exit 1
	fi
	if [ -z "$PACKAGE_BUGREPORT" ]; then
	printf >&2 '%s\n' \
	"$me: error: could not extract PACKAGE_BUGREPORT from configure.ac"
	exit 1
	fi

	# PACKAGE_TARNAME and PACKAGE_URL from the bootstrap autoconf should not
	# get copied into the configure script.
	PACKAGE_URL='<<not available>>'
	PACKAGE_TARNAME='<<not available>>'

	# Root for temporary partial installation tree.
	ACBOOTDIR=$(mktemp -d acboot.XXXXXXXXXX)
	ACBOOTDIR=$(realpath $ACBOOTDIR)

	# dosubst options infile outfile -- performs the substitutions that
	# config.status would perform on INFILE, creating OUTFILE. INFILE is
	# relative to the source directory, OUTFILE is relative to $ACBOOTDIR.
	# If OPTIONS is the letter 'x', OUTFILE is made executable after creation.
	dosubst ()
	{
	in=${2##*/}
	out="$ACBOOTDIR/$3"
	if [ -n "$verbose" ]; then
	printf '%s: creating %s\n' "$me" "$out"
	fi
	rm -f "$out"
	sed -e "s%@configure_input@%Generated from $in; do not edit by hand.%g" \
	-e "s%@M4@%$M4%g" \
	-e "s%@M4_DEBUGFILE@%$M4_DEBUGFILE%g" \
	-e "s%@M4_GNU@%$M4_GNU%g" \
	-e "s%@PACKAGE_BUGREPORT@%$PACKAGE_BUGREPORT%g" \
	-e "s%@PACKAGE_NAME@%$PACKAGE_NAME%g" \
	-e "s%@PACKAGE_STRING@%$PACKAGE_NAME $VERSION%g" \
	-e "s%@PACKAGE_TARNAME@%$PACKAGE_TARNAME%g" \
	-e "s%@PACKAGE_URL@%$PACKAGE_URL%g" \
	-e "s%@PACKAGE_VERSION@%$VERSION%g" \
	-e "s%@PERL@%$PERL%g" \
	-e "s%@PERL_FLOCK@%0%g" \
	-e "s%@RELEASE_YEAR@%$RELEASE_YEAR%g" \
	-e "s%@SHELL@%$BOOTSTRAP_SHELL%g" \
	-e "s%@VERSION@%$VERSION%g" \
	-e "s%@pkgdatadir@%$ACBOOTDIR/lib%g" \
	"$2" > "$out"
	if [ "$1" = "x" ]; then
	chmod +x "$out"
	fi
	}

	# Create the bootstrap installation.
	mkdir "$ACBOOTDIR"/bin "$ACBOOTDIR"/lib "$ACBOOTDIR"/tmp
	(
	cd "$ACBOOTDIR"/lib
	for sub in Autom4te autoconf m4sugar ; do
	if [ -n "$verbose" ]; then
	printf '%s: creating %s\n' "$me" "$ACBOOTDIR/lib/$sub"
	fi
	$LN_S ../../lib/$sub .
	done
	)

	# automake invokes autoconf, and autoconf and aclocal both invoke autom4te,
	# so we need to create both of them.
	dosubst x bin/autoconf.in bin/autoconf
	dosubst x bin/autom4te.in bin/autom4te
	dosubst . lib/autom4te.in lib/autom4te.cfg
	dosubst . lib/version.in lib/version.m4

	AUTOCONF="$ACBOOTDIR"/bin/autoconf
	AUTOM4TE="$ACBOOTDIR/bin/autom4te -M -C $ACBOOTDIR/tmp/autom4te.cache"
	export AUTOCONF AUTOM4TE

	# We can now do what autoreconf would have done.
	# Order is critical -- first aclocal, then autoconf, then automake.
	run ()
	{
	if [ -n "$verbose" ]; then
	printf '%s: running %s\n' "$me" "$*"
	fi
	"$@"
	}

	run $ACLOCAL -I m4 -Wall -Werror $subverbose $force
	run $AUTOCONF -Wall -Werror $subverbose $force
	run $AUTOMAKE --add-missing --copy -Wall -Werror $subverbose $force

	# Clean up.
	rm -rf "$ACBOOTDIR"