eclass/confutils.eclass - mirrors/cros/chromiumos/overlays/portage-stable - Git at Google

 # Copyright 1999-2008 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 # $Header: /var/cvsroot/gentoo-x86/eclass/confutils.eclass,v 1.22 2008/02/27 09:53:04 hollow Exp $

 # @ECLASS: confutils.eclass
 # @MAINTAINER:
 # Benedikt Böhm <hollow@gentoo.org>
 # @BLURB: utility functions to help with configuring a package
 # @DESCRIPTION:
 # The confutils eclass contains functions to handle use flag dependencies and
 # extended --with-*/--enable-* magic.
 #
 # Based on the PHP5 eclass by Stuart Herbert <stuart@stuartherbert.com>

 inherit eutils

 DESCRIPTION="Based on the ${ECLASS} eclass"

 # @VARIABLE: EBUILD_SUPPORTS_SHAREDEXT
 # @DESCRIPTION:
 # Set this variable to 1 if your ebuild supports shared extensions. You need to
 # call confutils_init() in pkg_setup() if you use this variable.
 if [[ ${EBUILD_SUPPORTS_SHAREDEXT} == 1 ]]; then
 	IUSE="sharedext"
 fi

 # @FUNCTION: confutils_init
 # @USAGE: [value]
 # @DESCRIPTION:
 # Call this function from your pkg_setup() function to initialize this eclass
 # if EBUILD_SUPPORTS_SHAREDEXT is enabled. If no value is given `shared' is used
 # by default.
 confutils_init() {
 	if [[ ${EBUILD_SUPPORTS_SHAREDEXT} == 1 ]] && use sharedext; then
 		shared="=${1:-shared}"
 	else
 		shared=
 	fi
 }

 # @FUNCTION: confutils_require_one
 # @USAGE: <flag> [more flags ...]
 # @DESCRIPTION:
 # Use this function to ensure exactly one of the specified USE flags have been
 # enabled
 confutils_require_one() {
 	local required_flags="$@"
 	local success=0

 	for flag in ${required_flags}; do
 		use ${flag} && ((success++))
 	done

 	[[ ${success} -eq 1 ]] && return

 	echo
 	eerror "You *must* enable *exactly* one of the following USE flags:"
 	eerror "  ${required_flags}"
 	eerror
 	eerror "You can do this by enabling *one* of these flag in /etc/portage/package.use:"

 	set -- ${required_flags}
 	eerror "     =${CATEGORY}/${PN}-${PVR} ${1}"
 	shift

 	for flag in $@; do
 		eerror "  OR =${CATEGORY}/${PN}-${PVR} ${flag}"
 	done

 	echo
 	die "Missing or conflicting USE flags"
 }

 # @FUNCTION: confutils_require_any
 # @USAGE: <flag> [more flags ...]
 # @DESCRIPTION:
 # Use this function to ensure one or more of the specified USE flags have been
 # enabled
 confutils_require_any() {
 	local required_flags="$@"
 	local success=0

 	for flag in ${required_flags}; do
 		use ${flag} && success=1
 	done

 	[[ ${success} -eq 1 ]] && return

 	echo
 	eerror "You *must* enable one or more of the following USE flags:"
 	eerror "  ${required_flags}"
 	eerror
 	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} ${required_flags}"
 	echo
 	die "Missing USE flags"
 }

 # @FUNCTION: confutils_require_built_with_all
 # @USAGE: <foreign> <flag> [more flags ...]
 # @DESCRIPTION:
 # Use this function to ensure all of the specified USE flags have been enabled
 # in the specified foreign package
 confutils_require_built_with_all() {
 	local foreign=$1 && shift
 	local required_flags="$@"

 	built_with_use ${foreign} ${required_flags} && return

 	echo
 	eerror "You *must* enable all of the following USE flags in ${foreign}:"
 	eerror "  ${required_flags}"
 	eerror
 	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
 	eerror "    ${foreign} ${required_flags}"
 	echo
 	die "Missing USE flags in ${foreign}"
 }

 # @FUNCTION: confutils_require_built_with_any
 # @USAGE: <foreign> <flag> [more flags ...]
 # @DESCRIPTION:
 # Use this function to ensure one or more of the specified USE flags have been
 # enabled in the specified foreign package
 confutils_require_built_with_any() {
 	local foreign=$1 && shift
 	local required_flags="$@"
 	local success=0

 	for flag in ${required_flags}; do
 		built_with_use ${foreign} ${flag} && success=1
 	done

 	[[ ${success} -eq 1 ]] && return

 	echo
 	eerror "You *must* enable one or more of the following USE flags in ${foreign}:"
 	eerror "  ${required_flags}"
 	eerror
 	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
 	eerror "    ${foreign} ${required_flags}"
 	echo
 	die "Missing USE flags in ${foreign}"
 }

 # @FUNCTION: confutils_use_conflict
 # @USAGE: <enabled flag> <conflicting flag> [more conflicting flags ...]
 # @DESCRIPTION:
 # Use this function to automatically complain to the user if conflicting USE
 # flags have been enabled
 confutils_use_conflict() {
 	use $1 || return

 	local my_flag="$1" && shift
 	local my_present=
 	local my_remove=

 	for flag in "$@"; do
 		if use ${flag}; then
 			my_present="${my_present} ${flag}"
 			my_remove="${my_remove} -${flag}"
 		fi
 	done

 	[[ -z "${my_present}" ]] && return

 	echo
 	eerror "USE flag '${my_flag}' conflicts with these USE flag(s):"
 	eerror "  ${my_present}"
 	eerror
 	eerror "You must disable these conflicting flags before you can emerge this package."
 	eerror "You can do this by disabling these flags in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} ${my_remove}"
 	eerror
 	eerror "You could disable this flag instead in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} -${my_flag}"
 	echo
 	die "Conflicting USE flags"
 }

 # @FUNCTION: confutils_use_depend_all
 # @USAGE: <enabled flag> <needed flag> [more needed flags ...]
 # @DESCRIPTION:
 # Use this function to automatically complain to the user if a USE flag depends
 # on another USE flag that hasn't been enabled
 confutils_use_depend_all() {
 	use $1 || return

 	local my_flag="$1" && shift
 	local my_missing=

 	for flag in "$@"; do
 		use ${flag} || my_missing="${my_missing} ${flag}"
 	done

 	[[ -z "${my_missing}" ]] && return

 	echo
 	eerror "USE flag '${my_flag}' needs these additional flag(s) set:"
 	eerror "  ${my_missing}"
 	eerror
 	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} ${my_missing}"
 	eerror
 	eerror "You could disable this flag instead in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} -${my_flag}"
 	echo
 	die "Need missing USE flags"
 }

 # @FUNCTION: confutils_use_depend_any
 # @USAGE: <enabled flag> <needed flag> [more needed flags ...]
 # @DESCRIPTION:
 # Use this function to automatically complain to the user if a USE flag depends
 # on another USE flag that hasn't been enabled
 confutils_use_depend_any() {
 	use $1 || return

 	local my_flag="$1" && shift
 	local my_found=
 	local my_missing=

 	for flag in "$@"; do
 		if use ${flag}; then
 			my_found="${my_found} ${flag}"
 		else
 			my_missing="${my_missing} ${flag}"
 		fi
 	done

 	[[ -n "${my_found}" ]] && return

 	echo
 	eerror "USE flag '${my_flag}' needs one or more of these additional flag(s) set:"
 	eerror "  ${my_missing}"
 	eerror
 	eerror "You can do this by enabling one of these flags in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} ${my_missing}"
 	eerror
 	eerror "You could disable this flag instead in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} -${my_flag}"
 	echo
 	die "Need missing USE flag(s)"
 }

 # @FUNCTION: confutils_use_depend_built_with_all
 # @USAGE: <enabled flag> <foreign> <needed flag> [more needed flags ...]
 # @DESCRIPTION:
 # Use this function to automatically complain to the user if a USE flag depends
 # on a USE flag in another package that hasn't been enabled
 confutils_use_depend_built_with_all() {
 	use $1 || return

 	local my_flag="$1" && shift
 	local foreign=$1 && shift
 	local required_flags="$@"

 	built_with_use ${foreign} ${required_flags} && return

 	echo
 	eerror "USE flag '${my_flag}' needs the following USE flags in ${foreign}:"
 	eerror "  ${required_flags}"
 	eerror
 	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
 	eerror "    ${foreign} ${required_flags}"
 	eerror
 	eerror "You could disable this flag instead in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} -${my_flag}"
 	echo
 	die "Missing USE flags in ${foreign}"
 }

 # @FUNCTION: confutils_use_depend_built_with_any
 # @USAGE: <enabled flag> <foreign> <needed flag> [more needed flags ...]
 # @DESCRIPTION:
 # Use this function to automatically complain to the user if a USE flag depends
 # on a USE flag in another package that hasn't been enabled
 confutils_use_depend_built_with_any() {
 	use $1 || return

 	local my_flag="$1" && shift
 	local foreign=$1 && shift
 	local required_flags="$@"
 	local success=0

 	for flag in ${required_flags}; do
 		built_with_use ${foreign} ${flag} && success=1
 	done

 	[[ ${success} -eq 1 ]] && return

 	echo
 	eerror "USE flag '${my_flag}' needs one or more of the following USE flags in ${foreign}:"
 	eerror "  ${required_flags}"
 	eerror
 	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
 	eerror "    ${foreign} ${required_flags}"
 	eerror
 	eerror "You could disable this flag instead in /etc/portage/package.use:"
 	eerror "    =${CATEGORY}/${PN}-${PVR} -${my_flag}"
 	echo
 	die "Missing USE flags in ${foreign}"
 }


 # internal function constructs the configure values for optional shared module
 # support and extra arguments
 _confutils_shared_suffix() {
 	local my_shared=

 	if [[ "$1" == "1" ]]; then
 		if [[ -n "${shared}" ]]; then
 			my_shared="${shared}"
 			if [[ -n "$2" ]]; then
 				my_shared="${my_shared},$2"
 			fi
 		elif [[ -n "$2" ]]; then
 			my_shared="=$2"
 		fi
 	else
 		if [[ -n "$2" ]]; then
 			my_shared="=$2"
 		fi
 	fi

 	echo "${my_shared}"
 }

 # @FUNCTION: enable_extension_disable
 # @USAGE: <extension> <flag> [msg]
 # @DESCRIPTION:
 # Use this function to disable an extension that is enabled by default.  This is
 # provided for those rare configure scripts that don't support a --enable for
 # the corresponding --disable.
 enable_extension_disable() {
 	local my_msg=${3:-$1}

 	if use "$2" ; then
 		einfo "  Enabling ${my_msg}"
 	else
 		my_conf="${my_conf} --disable-$1"
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_enable
 # @USAGE: <extension> <flag> [shared] [extra conf] [msg]
 # @DESCRIPTION:
 # This function is like use_enable(), except that it knows about enabling
 # modules as shared libraries, and it supports passing additional data with the
 # switch.
 enable_extension_enable() {
 	local my_shared=$(_confutils_shared_suffix $3 $4)
 	local my_msg=${5:-$1}

 	if use $2; then
 		my_conf="${my_conf} --enable-${1}${my_shared}"
 		einfo "  Enabling ${my_msg}"
 	else
 		my_conf="${my_conf} --disable-$1"
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_enableonly
 # @USAGE: <extension> <flag> [shared] [extra conf] [msg]
 # @DESCRIPTION:
 # This function is like use_enable(), except that it knows about enabling
 # modules as shared libraries, and it supports passing additional data with the
 # switch.  This function is provided for those rare configure scripts that support
 # --enable but not the corresponding --disable.
 enable_extension_enableonly() {
 	local my_shared=$(_confutils_shared_suffix $3 $4)
 	local my_msg=${5:-$1}

 	if use $2 ; then
 		my_conf="${my_conf} --enable-${1}${my_shared}"
 		einfo "  Enabling ${my_msg}"
 	else
 		# note: we deliberately do *not* use a --disable switch here
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_without
 # @USAGE: <extension> <flag> [msg]
 # @DESCRIPTION:
 # Use this function to disable an extension that is enabled by default. This
 # function is provided for those rare configure scripts that support --without
 # but not the corresponding --with
 enable_extension_without() {
 	local my_msg=${3:-$1}

 	if use "$2"; then
 		einfo "  Enabling ${my_msg}"
 	else
 		my_conf="${my_conf} --without-$1"
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_with
 # @USAGE: <extension> <flag> [shared] [extra conf] [msg]
 # @DESCRIPTION:
 # This function is like use_with(), except that it knows about enabling modules
 # as shared libraries, and it supports passing additional data with the switch.
 enable_extension_with() {
 	local my_shared=$(_confutils_shared_suffix $3 $4)
 	local my_msg=${5:-$1}

 	if use $2; then
 		my_conf="${my_conf} --with-${1}${my_shared}"
 		einfo "  Enabling ${my_msg}"
 	else
 		my_conf="${my_conf} --without-$1"
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_withonly
 # @USAGE: <extension> <flag> [shared] [extra conf] [msg]
 # @DESCRIPTION:
 # This function is like use_with(), except that it knows about enabling modules
 # as shared libraries, and it supports passing additional data with the switch.
 # This function is provided for those rare configure scripts that support --enable
 # but not the corresponding --disable.
 enable_extension_withonly() {
 	local my_shared=$(_confutils_shared_suffix $3 $4)
 	local my_msg=${5:-$1}

 	if use $2; then
 		my_conf="${my_conf} --with-${1}${my_shared}"
 		einfo "  Enabling ${my_msg}"
 	else
 		# note: we deliberately do *not* use a --without switch here
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_enable_built_with
 # @USAGE: <foreign> <flag> <extension> [shared] [extra conf] [msg]
 # @DESCRIPTION:
 # This function is like enable_extension_enable(), except that it
 # enables/disables modules based on a USE flag in a foreign package.
 enable_extension_enable_built_with() {
 	local my_shared=$(_confutils_shared_suffix $4 $5)
 	local my_msg=${6:-$3}

 	if built_with_use $1 $2; then
 		my_conf="${my_conf} --enable-${3}${my_shared}"
 		einfo "  Enabling ${my_msg}"
 	else
 		my_conf="${my_conf} --disable-$3"
 		einfo "  Disabling ${my_msg}"
 	fi
 }

 # @FUNCTION: enable_extension_with_built_with ()
 # @USAGE: <foreign> <flag> <extension> [shared] [extra conf] [msg]
 # @DESCRIPTION:
 # This function is like enable_extension_with(), except that it
 # enables/disables modules based on a USE flag in a foreign package.
 enable_extension_with_built_with() {
 	# legacy workaround
 	if [[ "$4" != "0" && "$4" != "1" ]]; then
 		enable_extension_with_built_with "$1" "$2" "$3" 0 "$4" "$5"
 		return
 	fi

 	local my_shared=$(_confutils_shared_suffix $4 $5)
 	local my_msg=${6:-$3}

 	if built_with_use $1 $2; then
 		my_conf="${my_conf} --with-${3}${my_shared}"
 		einfo "  Enabling ${my_msg}"
 	else
 		my_conf="${my_conf} --disable-$3"
 		einfo "  Disabling ${my_msg}"
 	fi
 }
	# Copyright 1999-2008 Gentoo Foundation
	# Distributed under the terms of the GNU General Public License v2
	# $Header: /var/cvsroot/gentoo-x86/eclass/confutils.eclass,v 1.22 2008/02/27 09:53:04 hollow Exp $

	# @ECLASS: confutils.eclass
	# @MAINTAINER:
	# Benedikt Böhm <hollow@gentoo.org>
	# @BLURB: utility functions to help with configuring a package
	# @DESCRIPTION:
	# The confutils eclass contains functions to handle use flag dependencies and
	# extended --with-/--enable- magic.
	#
	# Based on the PHP5 eclass by Stuart Herbert <stuart@stuartherbert.com>

	inherit eutils

	DESCRIPTION="Based on the ${ECLASS} eclass"

	# @VARIABLE: EBUILD_SUPPORTS_SHAREDEXT
	# @DESCRIPTION:
	# Set this variable to 1 if your ebuild supports shared extensions. You need to
	# call confutils_init() in pkg_setup() if you use this variable.
	if [[ ${EBUILD_SUPPORTS_SHAREDEXT} == 1 ]]; then
	IUSE="sharedext"
	fi

	# @FUNCTION: confutils_init
	# @USAGE: [value]
	# @DESCRIPTION:
	# Call this function from your pkg_setup() function to initialize this eclass
	# if EBUILD_SUPPORTS_SHAREDEXT is enabled. If no value is given `shared' is used
	# by default.
	confutils_init() {
	if [[ ${EBUILD_SUPPORTS_SHAREDEXT} == 1 ]] && use sharedext; then
	shared="=${1:-shared}"
	else
	shared=
	fi
	}

	# @FUNCTION: confutils_require_one
	# @USAGE: <flag> [more flags ...]
	# @DESCRIPTION:
	# Use this function to ensure exactly one of the specified USE flags have been
	# enabled
	confutils_require_one() {
	local required_flags="$@"
	local success=0

	for flag in ${required_flags}; do
	use ${flag} && ((success++))
	done

	[[ ${success} -eq 1 ]] && return

	echo
	eerror "You must enable exactly one of the following USE flags:"
	eerror " ${required_flags}"
	eerror
	eerror "You can do this by enabling one of these flag in /etc/portage/package.use:"

	set -- ${required_flags}
	eerror " =${CATEGORY}/${PN}-${PVR} ${1}"
	shift

	for flag in $@; do
	eerror " OR =${CATEGORY}/${PN}-${PVR} ${flag}"
	done

	echo
	die "Missing or conflicting USE flags"
	}

	# @FUNCTION: confutils_require_any
	# @USAGE: <flag> [more flags ...]
	# @DESCRIPTION:
	# Use this function to ensure one or more of the specified USE flags have been
	# enabled
	confutils_require_any() {
	local required_flags="$@"
	local success=0

	for flag in ${required_flags}; do
	use ${flag} && success=1
	done

	[[ ${success} -eq 1 ]] && return

	echo
	eerror "You must enable one or more of the following USE flags:"
	eerror " ${required_flags}"
	eerror
	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} ${required_flags}"
	echo
	die "Missing USE flags"
	}

	# @FUNCTION: confutils_require_built_with_all
	# @USAGE: <foreign> <flag> [more flags ...]
	# @DESCRIPTION:
	# Use this function to ensure all of the specified USE flags have been enabled
	# in the specified foreign package
	confutils_require_built_with_all() {
	local foreign=$1 && shift
	local required_flags="$@"

	built_with_use ${foreign} ${required_flags} && return

	echo
	eerror "You must enable all of the following USE flags in ${foreign}:"
	eerror " ${required_flags}"
	eerror
	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
	eerror " ${foreign} ${required_flags}"
	echo
	die "Missing USE flags in ${foreign}"
	}

	# @FUNCTION: confutils_require_built_with_any
	# @USAGE: <foreign> <flag> [more flags ...]
	# @DESCRIPTION:
	# Use this function to ensure one or more of the specified USE flags have been
	# enabled in the specified foreign package
	confutils_require_built_with_any() {
	local foreign=$1 && shift
	local required_flags="$@"
	local success=0

	for flag in ${required_flags}; do
	built_with_use ${foreign} ${flag} && success=1
	done

	[[ ${success} -eq 1 ]] && return

	echo
	eerror "You must enable one or more of the following USE flags in ${foreign}:"
	eerror " ${required_flags}"
	eerror
	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
	eerror " ${foreign} ${required_flags}"
	echo
	die "Missing USE flags in ${foreign}"
	}

	# @FUNCTION: confutils_use_conflict
	# @USAGE: <enabled flag> <conflicting flag> [more conflicting flags ...]
	# @DESCRIPTION:
	# Use this function to automatically complain to the user if conflicting USE
	# flags have been enabled
	confutils_use_conflict() {
	use $1 \|\| return

	local my_flag="$1" && shift
	local my_present=
	local my_remove=

	for flag in "$@"; do
	if use ${flag}; then
	my_present="${my_present} ${flag}"
	my_remove="${my_remove} -${flag}"
	fi
	done

	[[ -z "${my_present}" ]] && return

	echo
	eerror "USE flag '${my_flag}' conflicts with these USE flag(s):"
	eerror " ${my_present}"
	eerror
	eerror "You must disable these conflicting flags before you can emerge this package."
	eerror "You can do this by disabling these flags in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} ${my_remove}"
	eerror
	eerror "You could disable this flag instead in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} -${my_flag}"
	echo
	die "Conflicting USE flags"
	}

	# @FUNCTION: confutils_use_depend_all
	# @USAGE: <enabled flag> <needed flag> [more needed flags ...]
	# @DESCRIPTION:
	# Use this function to automatically complain to the user if a USE flag depends
	# on another USE flag that hasn't been enabled
	confutils_use_depend_all() {
	use $1 \|\| return

	local my_flag="$1" && shift
	local my_missing=

	for flag in "$@"; do
	use ${flag} \|\| my_missing="${my_missing} ${flag}"
	done

	[[ -z "${my_missing}" ]] && return

	echo
	eerror "USE flag '${my_flag}' needs these additional flag(s) set:"
	eerror " ${my_missing}"
	eerror
	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} ${my_missing}"
	eerror
	eerror "You could disable this flag instead in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} -${my_flag}"
	echo
	die "Need missing USE flags"
	}

	# @FUNCTION: confutils_use_depend_any
	# @USAGE: <enabled flag> <needed flag> [more needed flags ...]
	# @DESCRIPTION:
	# Use this function to automatically complain to the user if a USE flag depends
	# on another USE flag that hasn't been enabled
	confutils_use_depend_any() {
	use $1 \|\| return

	local my_flag="$1" && shift
	local my_found=
	local my_missing=

	for flag in "$@"; do
	if use ${flag}; then
	my_found="${my_found} ${flag}"
	else
	my_missing="${my_missing} ${flag}"
	fi
	done

	[[ -n "${my_found}" ]] && return

	echo
	eerror "USE flag '${my_flag}' needs one or more of these additional flag(s) set:"
	eerror " ${my_missing}"
	eerror
	eerror "You can do this by enabling one of these flags in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} ${my_missing}"
	eerror
	eerror "You could disable this flag instead in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} -${my_flag}"
	echo
	die "Need missing USE flag(s)"
	}

	# @FUNCTION: confutils_use_depend_built_with_all
	# @USAGE: <enabled flag> <foreign> <needed flag> [more needed flags ...]
	# @DESCRIPTION:
	# Use this function to automatically complain to the user if a USE flag depends
	# on a USE flag in another package that hasn't been enabled
	confutils_use_depend_built_with_all() {
	use $1 \|\| return

	local my_flag="$1" && shift
	local foreign=$1 && shift
	local required_flags="$@"

	built_with_use ${foreign} ${required_flags} && return

	echo
	eerror "USE flag '${my_flag}' needs the following USE flags in ${foreign}:"
	eerror " ${required_flags}"
	eerror
	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
	eerror " ${foreign} ${required_flags}"
	eerror
	eerror "You could disable this flag instead in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} -${my_flag}"
	echo
	die "Missing USE flags in ${foreign}"
	}

	# @FUNCTION: confutils_use_depend_built_with_any
	# @USAGE: <enabled flag> <foreign> <needed flag> [more needed flags ...]
	# @DESCRIPTION:
	# Use this function to automatically complain to the user if a USE flag depends
	# on a USE flag in another package that hasn't been enabled
	confutils_use_depend_built_with_any() {
	use $1 \|\| return

	local my_flag="$1" && shift
	local foreign=$1 && shift
	local required_flags="$@"
	local success=0

	for flag in ${required_flags}; do
	built_with_use ${foreign} ${flag} && success=1
	done

	[[ ${success} -eq 1 ]] && return

	echo
	eerror "USE flag '${my_flag}' needs one or more of the following USE flags in ${foreign}:"
	eerror " ${required_flags}"
	eerror
	eerror "You can do this by enabling these flags in /etc/portage/package.use:"
	eerror " ${foreign} ${required_flags}"
	eerror
	eerror "You could disable this flag instead in /etc/portage/package.use:"
	eerror " =${CATEGORY}/${PN}-${PVR} -${my_flag}"
	echo
	die "Missing USE flags in ${foreign}"
	}


	# internal function constructs the configure values for optional shared module
	# support and extra arguments
	_confutils_shared_suffix() {
	local my_shared=

	if [[ "$1" == "1" ]]; then
	if [[ -n "${shared}" ]]; then
	my_shared="${shared}"
	if [[ -n "$2" ]]; then
	my_shared="${my_shared},$2"
	fi
	elif [[ -n "$2" ]]; then
	my_shared="=$2"
	fi
	else
	if [[ -n "$2" ]]; then
	my_shared="=$2"
	fi
	fi

	echo "${my_shared}"
	}

	# @FUNCTION: enable_extension_disable
	# @USAGE: <extension> <flag> [msg]
	# @DESCRIPTION:
	# Use this function to disable an extension that is enabled by default. This is
	# provided for those rare configure scripts that don't support a --enable for
	# the corresponding --disable.
	enable_extension_disable() {
	local my_msg=${3:-$1}

	if use "$2" ; then
	einfo " Enabling ${my_msg}"
	else
	my_conf="${my_conf} --disable-$1"
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_enable
	# @USAGE: <extension> <flag> [shared] [extra conf] [msg]
	# @DESCRIPTION:
	# This function is like use_enable(), except that it knows about enabling
	# modules as shared libraries, and it supports passing additional data with the
	# switch.
	enable_extension_enable() {
	local my_shared=$(_confutils_shared_suffix $3 $4)
	local my_msg=${5:-$1}

	if use $2; then
	my_conf="${my_conf} --enable-${1}${my_shared}"
	einfo " Enabling ${my_msg}"
	else
	my_conf="${my_conf} --disable-$1"
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_enableonly
	# @USAGE: <extension> <flag> [shared] [extra conf] [msg]
	# @DESCRIPTION:
	# This function is like use_enable(), except that it knows about enabling
	# modules as shared libraries, and it supports passing additional data with the
	# switch. This function is provided for those rare configure scripts that support
	# --enable but not the corresponding --disable.
	enable_extension_enableonly() {
	local my_shared=$(_confutils_shared_suffix $3 $4)
	local my_msg=${5:-$1}

	if use $2 ; then
	my_conf="${my_conf} --enable-${1}${my_shared}"
	einfo " Enabling ${my_msg}"
	else
	# note: we deliberately do not use a --disable switch here
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_without
	# @USAGE: <extension> <flag> [msg]
	# @DESCRIPTION:
	# Use this function to disable an extension that is enabled by default. This
	# function is provided for those rare configure scripts that support --without
	# but not the corresponding --with
	enable_extension_without() {
	local my_msg=${3:-$1}

	if use "$2"; then
	einfo " Enabling ${my_msg}"
	else
	my_conf="${my_conf} --without-$1"
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_with
	# @USAGE: <extension> <flag> [shared] [extra conf] [msg]
	# @DESCRIPTION:
	# This function is like use_with(), except that it knows about enabling modules
	# as shared libraries, and it supports passing additional data with the switch.
	enable_extension_with() {
	local my_shared=$(_confutils_shared_suffix $3 $4)
	local my_msg=${5:-$1}

	if use $2; then
	my_conf="${my_conf} --with-${1}${my_shared}"
	einfo " Enabling ${my_msg}"
	else
	my_conf="${my_conf} --without-$1"
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_withonly
	# @USAGE: <extension> <flag> [shared] [extra conf] [msg]
	# @DESCRIPTION:
	# This function is like use_with(), except that it knows about enabling modules
	# as shared libraries, and it supports passing additional data with the switch.
	# This function is provided for those rare configure scripts that support --enable
	# but not the corresponding --disable.
	enable_extension_withonly() {
	local my_shared=$(_confutils_shared_suffix $3 $4)
	local my_msg=${5:-$1}

	if use $2; then
	my_conf="${my_conf} --with-${1}${my_shared}"
	einfo " Enabling ${my_msg}"
	else
	# note: we deliberately do not use a --without switch here
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_enable_built_with
	# @USAGE: <foreign> <flag> <extension> [shared] [extra conf] [msg]
	# @DESCRIPTION:
	# This function is like enable_extension_enable(), except that it
	# enables/disables modules based on a USE flag in a foreign package.
	enable_extension_enable_built_with() {
	local my_shared=$(_confutils_shared_suffix $4 $5)
	local my_msg=${6:-$3}

	if built_with_use $1 $2; then
	my_conf="${my_conf} --enable-${3}${my_shared}"
	einfo " Enabling ${my_msg}"
	else
	my_conf="${my_conf} --disable-$3"
	einfo " Disabling ${my_msg}"
	fi
	}

	# @FUNCTION: enable_extension_with_built_with ()
	# @USAGE: <foreign> <flag> <extension> [shared] [extra conf] [msg]
	# @DESCRIPTION:
	# This function is like enable_extension_with(), except that it
	# enables/disables modules based on a USE flag in a foreign package.
	enable_extension_with_built_with() {
	# legacy workaround
	if [[ "$4" != "0" && "$4" != "1" ]]; then
	enable_extension_with_built_with "$1" "$2" "$3" 0 "$4" "$5"
	return
	fi

	local my_shared=$(_confutils_shared_suffix $4 $5)
	local my_msg=${6:-$3}

	if built_with_use $1 $2; then
	my_conf="${my_conf} --with-${3}${my_shared}"
	einfo " Enabling ${my_msg}"
	else
	my_conf="${my_conf} --disable-$3"
	einfo " Disabling ${my_msg}"
	fi
	}