diff --git a/eclass/multilib-build.eclass b/eclass/multilib-build.eclass
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+++ b/eclass/multilib-build.eclass
@@ -0,0 +1,673 @@
+# Copyright 1999-2018 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: multilib-build.eclass
+# @MAINTAINER:
+# gx86-multilib team <multilib@gentoo.org>
+# @AUTHOR:
+# Author: Michał Górny <mgorny@gentoo.org>
+# @SUPPORTED_EAPIS: 4 5 6 7
+# @BLURB: flags and utility functions for building multilib packages
+# @DESCRIPTION:
+# The multilib-build.eclass exports USE flags and utility functions
+# necessary to build packages for multilib in a clean and uniform
+# manner.
+#
+# Please note that dependency specifications for multilib-capable
+# dependencies shall use the USE dependency string in ${MULTILIB_USEDEP}
+# to properly request multilib enabled.
+
+if [[ ! ${_MULTILIB_BUILD} ]]; then
+
+# EAPI=4 is required for meaningful MULTILIB_USEDEP.
+case ${EAPI:-0} in
+	4|5|6|7) ;;
+	*) die "EAPI=${EAPI} is not supported" ;;
+esac
+
+[[ ${EAPI} == [45] ]] && inherit eutils
+inherit multibuild multilib
+
+# @ECLASS-VARIABLE: _MULTILIB_FLAGS
+# @INTERNAL
+# @DESCRIPTION:
+# The list of multilib flags and corresponding ABI values. If the same
+# flag is reused for multiple ABIs (e.g. x86 on Linux&FreeBSD), multiple
+# ABIs may be separated by commas.
+#
+# Please contact multilib before modifying this list. This way we can
+# ensure that every *preliminary* work is done and the multilib can be
+# extended safely.
+_MULTILIB_FLAGS=(
+	abi_x86_32:x86,x86_fbsd,x86_freebsd,x86_linux,x86_macos,x86_solaris
+	abi_x86_64:amd64,amd64_fbsd,x64_freebsd,amd64_linux,x64_macos,x64_solaris
+	abi_x86_x32:x32
+	abi_mips_n32:n32
+	abi_mips_n64:n64
+	abi_mips_o32:o32
+	abi_ppc_32:ppc,ppc_aix,ppc_macos
+	abi_ppc_64:ppc64
+	abi_s390_32:s390
+	abi_s390_64:s390x
+)
+readonly _MULTILIB_FLAGS
+
+# @ECLASS-VARIABLE: MULTILIB_COMPAT
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# List of multilib ABIs supported by the ebuild. If unset, defaults to
+# all ABIs supported by the eclass.
+#
+# This variable is intended for use in prebuilt multilib packages that
+# can provide binaries only for a limited set of ABIs. If ABIs need to
+# be limited due to a bug in source code, package.use.mask is to be used
+# instead. Along with MULTILIB_COMPAT, KEYWORDS should contain '-*'.
+#
+# Note that setting this variable effectively disables support for all
+# other ABIs, including other architectures. For example, specifying
+# abi_x86_{32,64} disables support for MIPS as well.
+#
+# The value of MULTILIB_COMPAT determines the value of IUSE. If set, it
+# also enables REQUIRED_USE constraints.
+#
+# Example use:
+# @CODE
+# # Upstream provides binaries for x86 & amd64 only
+# MULTILIB_COMPAT=( abi_x86_{32,64} )
+# @CODE
+
+# @ECLASS-VARIABLE: MULTILIB_USEDEP
+# @DESCRIPTION:
+# The USE-dependency to be used on dependencies (libraries) needing
+# to support multilib as well.
+#
+# Example use:
+# @CODE
+# RDEPEND="dev-libs/libfoo[${MULTILIB_USEDEP}]
+#	net-libs/libbar[ssl,${MULTILIB_USEDEP}]"
+# @CODE
+
+# @ECLASS-VARIABLE: MULTILIB_ABI_FLAG
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# The complete ABI name. Resembles the USE flag name.
+#
+# This is set within multilib_foreach_abi(),
+# multilib_parallel_foreach_abi() and multilib-minimal sub-phase
+# functions.
+#
+# It may be null (empty) when the build is done on ABI not controlled
+# by a USE flag (e.g. on non-multilib arch or when using multilib
+# portage). The build will always be done for a single ABI then.
+#
+# Example value:
+# @CODE
+# abi_x86_64
+# @CODE
+
+_multilib_build_set_globals() {
+	local flags=( "${_MULTILIB_FLAGS[@]%:*}" )
+
+	if [[ ${MULTILIB_COMPAT[@]} ]]; then
+		# Validate MULTILIB_COMPAT and filter out the flags.
+		local f
+		for f in "${MULTILIB_COMPAT[@]}"; do
+			if ! has "${f}" "${flags[@]}"; then
+				die "Invalid value in MULTILIB_COMPAT: ${f}"
+			fi
+		done
+
+		flags=( "${MULTILIB_COMPAT[@]}" )
+
+		REQUIRED_USE="|| ( ${flags[*]} )"
+	fi
+
+	local usedeps=${flags[@]/%/(-)?}
+
+	IUSE=${flags[*]}
+	MULTILIB_USEDEP=${usedeps// /,}
+	readonly MULTILIB_USEDEP
+}
+_multilib_build_set_globals
+unset -f _multilib_build_set_globals
+
+# @FUNCTION: multilib_get_enabled_abis
+# @DESCRIPTION:
+# Return the ordered list of enabled ABIs if multilib builds
+# are enabled. The best (most preferred) ABI will come last.
+#
+# If multilib is disabled, the default ABI will be returned
+# in order to enforce consistent testing with multilib code.
+multilib_get_enabled_abis() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local pairs=( $(multilib_get_enabled_abi_pairs) )
+	echo "${pairs[@]#*.}"
+}
+
+# @FUNCTION: multilib_get_enabled_abi_pairs
+# @DESCRIPTION:
+# Return the ordered list of enabled <use-flag>.<ABI> pairs
+# if multilib builds are enabled. The best (most preferred)
+# ABI will come last.
+#
+# If multilib is disabled, the default ABI will be returned
+# along with empty <use-flag>.
+multilib_get_enabled_abi_pairs() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local abis=( $(get_all_abis) )
+
+	local abi i found
+	for abi in "${abis[@]}"; do
+		for i in "${_MULTILIB_FLAGS[@]}"; do
+			local m_abis=${i#*:} m_abi
+			local m_flag=${i%:*}
+
+			# split on ,; we can't switch IFS for function scope because
+			# paludis is broken (bug #486592), and switching it locally
+			# for the split is more complex than cheating like this
+			for m_abi in ${m_abis//,/ }; do
+				if [[ ${m_abi} == ${abi} ]] \
+					&& { [[ ! "${MULTILIB_COMPAT[@]}" ]] || has "${m_flag}" "${MULTILIB_COMPAT[@]}"; } \
+					&& use "${m_flag}"
+				then
+					echo "${m_flag}.${abi}"
+					found=1
+					break 2
+				fi
+			done
+		done
+	done
+
+	if [[ ! ${found} ]]; then
+		# ${ABI} can be used to override the fallback (multilib-portage),
+		# ${DEFAULT_ABI} is the safe fallback.
+		local abi=${ABI:-${DEFAULT_ABI}}
+
+		debug-print "${FUNCNAME}: no ABIs enabled, fallback to ${abi}"
+		debug-print "${FUNCNAME}: ABI=${ABI}, DEFAULT_ABI=${DEFAULT_ABI}"
+		echo ".${abi}"
+	fi
+}
+
+# @FUNCTION: _multilib_multibuild_wrapper
+# @USAGE: <argv>...
+# @INTERNAL
+# @DESCRIPTION:
+# Initialize the environment for ABI selected for multibuild.
+_multilib_multibuild_wrapper() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local ABI=${MULTIBUILD_VARIANT#*.}
+	local -r MULTILIB_ABI_FLAG=${MULTIBUILD_VARIANT%.*}
+
+	multilib_toolchain_setup "${ABI}"
+	readonly ABI
+	"${@}"
+}
+
+# @FUNCTION: multilib_foreach_abi
+# @USAGE: <argv>...
+# @DESCRIPTION:
+# If multilib support is enabled, sets the toolchain up for each
+# supported ABI along with the ABI variable and correct BUILD_DIR,
+# and runs the given commands with them.
+#
+# If multilib support is disabled, it just runs the commands. No setup
+# is done.
+multilib_foreach_abi() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local MULTIBUILD_VARIANTS=( $(multilib_get_enabled_abi_pairs) )
+	multibuild_foreach_variant _multilib_multibuild_wrapper "${@}"
+}
+
+# @FUNCTION: multilib_parallel_foreach_abi
+# @USAGE: <argv>...
+# @DESCRIPTION:
+# If multilib support is enabled, sets the toolchain up for each
+# supported ABI along with the ABI variable and correct BUILD_DIR,
+# and runs the given commands with them.
+#
+# If multilib support is disabled, it just runs the commands. No setup
+# is done.
+#
+# This function used to run multiple commands in parallel. Now it's just
+# a deprecated alias to multilib_foreach_abi.
+multilib_parallel_foreach_abi() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local MULTIBUILD_VARIANTS=( $(multilib_get_enabled_abi_pairs) )
+	multibuild_foreach_variant _multilib_multibuild_wrapper "${@}"
+}
+
+# @FUNCTION: multilib_for_best_abi
+# @USAGE: <argv>...
+# @DESCRIPTION:
+# Runs the given command with setup for the 'best' (usually native) ABI.
+multilib_for_best_abi() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	[[ ${EAPI} == [45] ]] || die "${FUNCNAME} is banned in EAPI ${EAPI}, use multilib_is_native_abi() instead"
+
+	eqawarn "QA warning: multilib_for_best_abi() function is deprecated and should"
+	eqawarn "not be used. The multilib_is_native_abi() check may be used instead."
+
+	local MULTIBUILD_VARIANTS=( $(multilib_get_enabled_abi_pairs) )
+
+	multibuild_for_best_variant _multilib_multibuild_wrapper "${@}"
+}
+
+# @FUNCTION: multilib_check_headers
+# @DESCRIPTION:
+# Check whether the header files are consistent between ABIs.
+#
+# This function needs to be called after each ABI's installation phase.
+# It obtains the header file checksums and compares them with previous
+# runs (if any). Dies if header files differ.
+multilib_check_headers() {
+	_multilib_header_cksum() {
+		set -o pipefail
+
+		if [[ -d ${ED%/}/usr/include ]]; then
+			find "${ED%/}"/usr/include -type f \
+				-exec cksum {} + | sort -k2
+		fi
+	}
+
+	local cksum cksum_prev
+	local cksum_file=${T}/.multilib_header_cksum
+	cksum=$(_multilib_header_cksum) || die
+	unset -f _multilib_header_cksum
+
+	if [[ -f ${cksum_file} ]]; then
+		cksum_prev=$(< "${cksum_file}") || die
+
+		if [[ ${cksum} != ${cksum_prev} ]]; then
+			echo "${cksum}" > "${cksum_file}.new" || die
+
+			eerror "Header files have changed between ABIs."
+
+			if type -p diff &>/dev/null; then
+				eerror "$(diff -du "${cksum_file}" "${cksum_file}.new")"
+			else
+				eerror "Old checksums in: ${cksum_file}"
+				eerror "New checksums in: ${cksum_file}.new"
+			fi
+
+			die "Header checksum mismatch, aborting."
+		fi
+	else
+		echo "${cksum}" > "${cksum_file}" || die
+	fi
+}
+
+# @FUNCTION: multilib_copy_sources
+# @DESCRIPTION:
+# Create a single copy of the package sources for each enabled ABI.
+#
+# The sources are always copied from initial BUILD_DIR (or S if unset)
+# to ABI-specific build directory matching BUILD_DIR used by
+# multilib_foreach_abi().
+multilib_copy_sources() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local MULTIBUILD_VARIANTS=( $(multilib_get_enabled_abi_pairs) )
+	multibuild_copy_sources
+}
+
+# @ECLASS-VARIABLE: MULTILIB_WRAPPED_HEADERS
+# @DESCRIPTION:
+# A list of headers to wrap for multilib support. The listed headers
+# will be moved to a non-standard location and replaced with a file
+# including them conditionally to current ABI.
+#
+# This variable has to be a bash array. Paths shall be relative to
+# installation root (${ED}), and name regular files. Recursive wrapping
+# is not supported.
+#
+# Please note that header wrapping is *discouraged*. It is preferred to
+# install all headers in a subdirectory of libdir and use pkg-config to
+# locate the headers. Some C preprocessors will not work with wrapped
+# headers.
+#
+# Example:
+# @CODE
+# MULTILIB_WRAPPED_HEADERS=(
+#	/usr/include/foobar/config.h
+# )
+# @CODE
+
+# @ECLASS-VARIABLE: MULTILIB_CHOST_TOOLS
+# @DESCRIPTION:
+# A list of tool executables to preserve for each multilib ABI.
+# The listed executables will be renamed to ${CHOST}-${basename},
+# and the native variant will be symlinked to the generic name.
+#
+# This variable has to be a bash array. Paths shall be relative to
+# installation root (${ED}), and name regular files or symbolic
+# links to regular files. Recursive wrapping is not supported.
+#
+# If symbolic link is passed, both symlink path and symlink target
+# will be changed. As a result, the symlink target is expected
+# to be wrapped as well (either by listing in MULTILIB_CHOST_TOOLS
+# or externally).
+#
+# Please note that tool wrapping is *discouraged*. It is preferred to
+# install pkg-config files for each ABI, and require reverse
+# dependencies to use that.
+#
+# Packages that search for tools properly (e.g. using AC_PATH_TOOL
+# macro) will find the wrapper executables automatically. Other packages
+# will need explicit override of tool paths.
+#
+# Example:
+# @CODE
+# MULTILIB_CHOST_TOOLS=(
+#	/usr/bin/foo-config
+# )
+
+# @CODE
+# @FUNCTION: multilib_prepare_wrappers
+# @USAGE: [<install-root>]
+# @DESCRIPTION:
+# Perform the preparation of all kinds of wrappers for the current ABI.
+# This function shall be called once per each ABI, after installing
+# the files to be wrapped.
+#
+# Takes an optional custom <install-root> from which files will be
+# used. If no root is specified, uses ${ED}.
+#
+# The files to be wrapped are specified using separate variables,
+# e.g. MULTILIB_WRAPPED_HEADERS. Those variables shall not be changed
+# between the successive calls to multilib_prepare_wrappers
+# and multilib_install_wrappers.
+#
+# After all wrappers are prepared, multilib_install_wrappers shall
+# be called to commit them to the installation tree.
+multilib_prepare_wrappers() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	[[ ${#} -le 1 ]] || die "${FUNCNAME}: too many arguments"
+
+	local root=${1:-${ED%/}}
+	local f
+
+	if [[ ${COMPLETE_MULTILIB} == yes ]]; then
+		# symlink '${CHOST}-foo -> foo' to support abi-wrapper while
+		# keeping ${CHOST}-foo calls correct.
+
+		for f in "${MULTILIB_CHOST_TOOLS[@]}"; do
+			# drop leading slash if it's there
+			f=${f#/}
+
+			local dir=${f%/*}
+			local fn=${f##*/}
+
+			ln -s "${fn}" "${root}/${dir}/${CHOST}-${fn}" || die
+		done
+
+		return
+	fi
+
+	for f in "${MULTILIB_CHOST_TOOLS[@]}"; do
+		# drop leading slash if it's there
+		f=${f#/}
+
+		local dir=${f%/*}
+		local fn=${f##*/}
+
+		if [[ -L ${root}/${f} ]]; then
+			# rewrite the symlink target
+			local target
+			target=$(readlink "${root}/${f}") || die
+			local target_dir target_fn=${target##*/}
+
+			[[ ${target} == */* ]] && target_dir=${target%/*}
+
+			ln -f -s "${target_dir+${target_dir}/}${CHOST}-${target_fn}" \
+				"${root}/${f}" || die
+		fi
+
+		mv "${root}/${f}" "${root}/${dir}/${CHOST}-${fn}" || die
+
+		# symlink the native one back
+		if multilib_is_native_abi; then
+			ln -s "${CHOST}-${fn}" "${root}/${f}" || die
+		fi
+	done
+
+	if [[ ${MULTILIB_WRAPPED_HEADERS[@]} ]]; then
+		# If abi_flag is unset, then header wrapping is unsupported on
+		# this ABI. This means the arch doesn't support multilib at all
+		# -- in this case, the headers are not wrapped and everything
+		# works as expected.
+
+		if [[ ${MULTILIB_ABI_FLAG} ]]; then
+			for f in "${MULTILIB_WRAPPED_HEADERS[@]}"; do
+				# drop leading slash if it's there
+				f=${f#/}
+
+				if [[ ${f} != usr/include/* ]]; then
+					die "Wrapping headers outside of /usr/include is not supported at the moment."
+				fi
+				# and then usr/include
+				f=${f#usr/include}
+
+				local dir=${f%/*}
+
+				# Some ABIs may have install less files than others.
+				if [[ -f ${root}/usr/include${f} ]]; then
+					local wrapper=${ED%/}/tmp/multilib-include${f}
+
+					if [[ ! -f ${ED%/}/tmp/multilib-include${f} ]]; then
+						dodir "/tmp/multilib-include${dir}"
+						# a generic template
+						cat > "${wrapper}" <<_EOF_ || die
+/* This file is auto-generated by multilib-build.eclass
+ * as a multilib-friendly wrapper. For the original content,
+ * please see the files that are #included below.
+ */
+
+#if defined(__x86_64__) /* amd64 */
+#	if defined(__ILP32__) /* x32 ABI */
+#		error "abi_x86_x32 not supported by the package."
+#	else /* 64-bit ABI */
+#		error "abi_x86_64 not supported by the package."
+#	endif
+#elif defined(__i386__) /* plain x86 */
+#	error "abi_x86_32 not supported by the package."
+#elif defined(__mips__)
+#   if(_MIPS_SIM == _ABIN32) /* n32 */
+#       error "abi_mips_n32 not supported by the package."
+#   elif(_MIPS_SIM == _ABI64) /* n64 */
+#       error "abi_mips_n64 not supported by the package."
+#   elif(_MIPS_SIM == _ABIO32) /* o32 */
+#       error "abi_mips_o32 not supported by the package."
+#   endif
+#elif defined(__sparc__)
+#	if defined(__arch64__)
+#       error "abi_sparc_64 not supported by the package."
+#	else
+#       error "abi_sparc_32 not supported by the package."
+#	endif
+#elif defined(__s390__)
+#	if defined(__s390x__)
+#       error "abi_s390_64 not supported by the package."
+#	else
+#       error "abi_s390_32 not supported by the package."
+#	endif
+#elif defined(__powerpc__) || defined(__ppc__)
+#	if defined(__powerpc64__) || defined(__ppc64__)
+#       error "abi_ppc_64 not supported by the package."
+#	else
+#       error "abi_ppc_32 not supported by the package."
+#	endif
+#elif defined(SWIG) /* https://sourceforge.net/p/swig/bugs/799/ */
+#	error "Native ABI not supported by the package."
+#else
+#	error "No ABI matched, please report a bug to bugs.gentoo.org"
+#endif
+_EOF_
+					fi
+
+					if ! grep -q "${MULTILIB_ABI_FLAG} " "${wrapper}"
+					then
+						die "Flag ${MULTILIB_ABI_FLAG} not listed in wrapper template. Please report a bug to https://bugs.gentoo.org."
+					fi
+
+					# $CHOST shall be set by multilib_toolchain_setup
+					dodir "/tmp/multilib-include/${CHOST}${dir}"
+					mv "${root}/usr/include${f}" "${ED%/}/tmp/multilib-include/${CHOST}${dir}/" || die
+
+					# Note: match a space afterwards to avoid collision potential.
+					sed -e "/${MULTILIB_ABI_FLAG} /s&error.*&include <${CHOST}${f}>&" \
+						-i "${wrapper}" || die
+
+					# Needed for swig.
+					if multilib_is_native_abi; then
+						sed -e "/Native ABI/s&error.*&include <${CHOST}${f}>&" \
+							-i "${wrapper}" || die
+					fi
+				fi
+			done
+		fi
+	fi
+}
+
+# @FUNCTION: multilib_install_wrappers
+# @USAGE: [<install-root>]
+# @DESCRIPTION:
+# Install the previously-prepared wrappers. This function shall
+# be called once, after all wrappers were prepared.
+#
+# Takes an optional custom <install-root> to which the wrappers will be
+# installed. If no root is specified, uses ${ED}. There is no need to
+# use the same root as when preparing the wrappers.
+#
+# The files to be wrapped are specified using separate variables,
+# e.g. MULTILIB_WRAPPED_HEADERS. Those variables shall not be changed
+# between the calls to multilib_prepare_wrappers
+# and multilib_install_wrappers.
+multilib_install_wrappers() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	[[ ${#} -le 1 ]] || die "${FUNCNAME}: too many arguments"
+
+	[[ ${COMPLETE_MULTILIB} == yes ]] && return
+
+	local root=${1:-${ED}}
+
+	if [[ -d ${ED%/}/tmp/multilib-include ]]; then
+		multibuild_merge_root \
+			"${ED%/}"/tmp/multilib-include "${root}"/usr/include
+		# it can fail if something else uses /tmp
+		rmdir "${ED%/}"/tmp &>/dev/null
+	fi
+}
+
+# @FUNCTION: multilib_is_native_abi
+# @DESCRIPTION:
+# Determine whether the currently built ABI is the profile native.
+# Return true status (0) if that is true, otherwise false (1).
+multilib_is_native_abi() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	[[ ${#} -eq 0 ]] || die "${FUNCNAME}: too many arguments"
+
+	[[ ${COMPLETE_MULTILIB} == yes || ${ABI} == ${DEFAULT_ABI} ]]
+}
+
+# @FUNCTION: multilib_build_binaries
+# @DESCRIPTION:
+# Deprecated synonym for multilib_is_native_abi
+multilib_build_binaries() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	[[ ${EAPI} == [45] ]] || die "${FUNCNAME} is banned in EAPI ${EAPI}, use multilib_is_native_abi() instead"
+
+	eqawarn "QA warning: multilib_build_binaries is deprecated. Please use the equivalent"
+	eqawarn "multilib_is_native_abi function instead."
+
+	multilib_is_native_abi "${@}"
+}
+
+# @FUNCTION: multilib_native_use_with
+# @USAGE: <flag> [<opt-name> [<opt-value>]]
+# @DESCRIPTION:
+# Output --with configure option alike use_with if USE <flag> is enabled
+# and executables are being built (multilib_is_native_abi is true).
+# Otherwise, outputs --without configure option. Arguments are the same
+# as for use_with in the EAPI.
+multilib_native_use_with() {
+	if multilib_is_native_abi; then
+		use_with "${@}"
+	else
+		echo "--without-${2:-${1}}"
+	fi
+}
+
+# @FUNCTION: multilib_native_use_enable
+# @USAGE: <flag> [<opt-name> [<opt-value>]]
+# @DESCRIPTION:
+# Output --enable configure option alike use_enable if USE <flag>
+# is enabled and executables are being built (multilib_is_native_abi
+# is true). Otherwise, outputs --disable configure option. Arguments are
+# the same as for use_enable in the EAPI.
+multilib_native_use_enable() {
+	if multilib_is_native_abi; then
+		use_enable "${@}"
+	else
+		echo "--disable-${2:-${1}}"
+	fi
+}
+
+# @FUNCTION: multilib_native_enable
+# @USAGE: <opt-name> [<opt-value>]
+# @DESCRIPTION:
+# Output --enable configure option if executables are being built
+# (multilib_is_native_abi is true). Otherwise, output --disable configure
+# option.
+multilib_native_enable() {
+	if multilib_is_native_abi; then
+		echo "--enable-${1}${2+=${2}}"
+	else
+		echo "--disable-${1}"
+	fi
+}
+
+# @FUNCTION: multilib_native_with
+# @USAGE: <opt-name> [<opt-value>]
+# @DESCRIPTION:
+# Output --with configure option if executables are being built
+# (multilib_is_native_abi is true). Otherwise, output --without configure
+# option.
+multilib_native_with() {
+	if multilib_is_native_abi; then
+		echo "--with-${1}${2+=${2}}"
+	else
+		echo "--without-${1}"
+	fi
+}
+
+# @FUNCTION: multilib_native_usex
+# @USAGE: <flag> [<true1> [<false1> [<true2> [<false2>]]]]
+# @DESCRIPTION:
+# Output the concatenation of <true1> (or 'yes' if unspecified)
+# and <true2> if USE <flag> is enabled and executables are being built
+# (multilib_is_native_abi is true). Otherwise, output the concatenation
+# of <false1> (or 'no' if unspecified) and <false2>. Arguments
+# are the same as for usex in the EAPI.
+#
+# Note: in EAPI 4 you need to inherit eutils to use this function.
+multilib_native_usex() {
+	if multilib_is_native_abi; then
+		usex "${@}"
+	else
+		echo "${3-no}${5}"
+	fi
+}
+
+_MULTILIB_BUILD=1
+fi