darwin_symlink_sdk() {

	# setup MacOSX.sdk symlink for GCC/clang, this should probably be

	# managed using an eselect module in the future

	rm -f "${ROOT}/MacOSX.sdk"

	local SDKPATH=$(xcrun --show-sdk-path --sdk macosx)

	local SDKVERSION=$(xcrun --show-sdk-version --sdk macosx)

	( cd ${ROOT} && ln -s "${SDKPATH}" MacOSX.sdk )

	einfo "using system sources (${SDKVERSION}) from: ${SDKPATH}"

}

darwin_include_paths() {

	local SDKPATH="${ROOT}/MacOSX.sdk"

	export C_INCLUDE_PATH="${SDKPATH}/usr/include"

	# we require command line tools. This allows stage2 to progress.

	export CPLUS_INCLUDE_PATH="/Library/Developer/CommandLineTools/usr/include/c++/v1:${C_INCLUDE_PATH}"

}

					# sys-devel/binutils-apple requires sys-libs/tapi, but we

					# cannot build it first. so, stage2 needs to bootstrap it.

					#linker="sys-libs/tapi sys-devel/binutils-apple"

					if [[ ! -d /usr/include ]]; then

						darwin_symlink_sdk

						darwin_include_paths

					fi

bootstrap_libtapi() {

	# grab the libtapi headers (which are actually compiled headers)

	# but link with libtapi.dylib from CommaandLineTools

	local PN PV A S

	PN=libtapi

	PV=1000.10.8_1

	rev=${CHOST##*darwin}

	A=${PN}-${PV}.darwin_${rev}.x86_64.tbz2

	einfo "Bootstrapping ${A%-*} (link to system dylib)"

	efetch "http://packages.macports.org/libtapi/${A}"

	einfo "Unpacking ${A%-*}"

	S="${PORTAGE_TMPDIR}/${PN}-${PV}"

	rm -rf "${S}"

	mkdir -p "${S}"

	cd "${S}"

	bzip2 -dc "${DISTDIR}/${A}" | tar -xf - || return 1

	cp -r opt/local/include/tapi "${ROOT}"/tmp/usr/include || return 1

	# to link with this lib, pass '-client_name ld' in LDFLAGS

	ln -s /Library/Developer/CommandLineTools/usr/lib/libtapi.dylib "${ROOT}"/tmp/usr/lib

}

	# rhash (dep of cmake) configure can't find the openssl/libressl.

	# ssl use flag allows RHash to "use optimized algorithms"

	# but RHash will work fine without, so disable during bootstrap.

	echo "app-crypt/rhash -ssl" >> "${ROOT}"/tmp/etc/portage/package.use

	if [[ ${CHOST} == *-darwin* ]]; then

		# libtapi.dylib is needed to build the binutils-apple linker,

		# but building sys-libs/tapi requires llvm to be installed

		# because it uses llvm.eclass which checks for which version

		# of llvm is installed. Also, building libtapi includes

		# re-building the sources of llvm & clang to get some internal

		# binaries that don't get installed, but we haven't installed

		# the llvm deps yet. So, we can't install tapi via portage yet.

		[[ ${DARWIN_USE_GCC} == 1 ]] \

			|| [[ -f "${ROOT}"/tmp/usr/lib/libtapi.dylib ]] \

			|| (bootstrap_libtapi) || return 1

	fi