diff --git a/a/Makefile b/b/Makefile
--- a/a/Makefile
+++ b/b/Makefile
@@ -5,7 +5,8 @@ PN = gcc-config
 PV = git
 P = $(PN)-$(PV)
 
-PREFIX = /usr
+EPREFIX =
+PREFIX = $(EPREFIX)/usr
 BINDIR = $(PREFIX)/bin
 SUBLIBDIR = lib
 LIBDIR = $(PREFIX)/$(SUBLIBDIR)
@@ -16,6 +17,11 @@ INSTALL_EXE = install -m 755
 
 all: wrapper
 
+wrapper.c: wrapper.c.in
+	sed \
+		-e 's:@GENTOO_PORTAGE_EPREFIX@:$(EPREFIX):g' \
+		wrapper.c.in > wrapper.c
+
 clean:
 	rm -f wrapper *.o core
 
@@ -23,6 +29,7 @@ install: all
 	$(MKDIR_P) $(DESTDIR)$(BINDIR) $(DESTDIR)$(LIBEXECDIR)
 	$(INSTALL_EXE) wrapper $(DESTDIR)$(LIBEXECDIR)/$(PN)
 	sed \
+		-e 's:@GENTOO_PORTAGE_EPREFIX@:$(EPREFIX):g' \
 		-e 's:@GENTOO_LIBDIR@:$(SUBLIBDIR):g' \
 		-e 's:@PV@:$(PV):g' \
 		gcc-config > $(DESTDIR)$(BINDIR)/gcc-config
diff --git a/a/gcc-config b/b/gcc-config
index 18d0b48..935b4c8 100755
--- a/a/gcc-config
+++ b/b/gcc-config
@@ -9,14 +9,17 @@
 : ${ROOT:=/}
 [[ ${ROOT} != */ ]] && ROOT="${ROOT}/"
 [[ ${ROOT} != /* ]] && ROOT="${PWD%/}/${ROOT}"
+BPREFIX="@GENTOO_PORTAGE_EPREFIX@"
+: ${EPREFIX:=${BPREFIX}}
+EROOT="${ROOT%/}${EPREFIX}/"
 
 cd /
 
 trap ":" INT QUIT TSTP
 
 argv0=${0##*/}
-source /etc/init.d/functions.sh || {
-	echo "${argv0}: Could not source /etc/init.d/functions.sh!" 1>&2
+source "${BPREFIX}"/etc/init.d/functions.sh || {
+	echo "${argv0}: Could not source ${BPREFIX}/etc/init.d/functions.sh!" 1>&2
 	exit 1
 }
 esyslog() { :; }
@@ -84,16 +87,16 @@ try_real_hard_to_find_CHOST() {
 	#
 
 	local varname=${1:-CHOST}
-	local conf=${ROOT}/etc/portage/make.conf
-	if [[ ! -e ${conf} && -e ${ROOT}/etc/make.conf ]] ; then
-		conf=${ROOT}/etc/make.conf
+	local conf=${EROOT}/etc/portage/make.conf
+	if [[ ! -e ${conf} && -e ${EROOT}/etc/make.conf ]] ; then
+		conf=${EROOT}/etc/make.conf
 	fi
 	local ret=$(source "${conf}" 2>/dev/null ; echo ${!varname})
 	if [[ -z ${ret} ]] ; then
 		# newer portage supports spaces between the var and =
 		# CHOST     =  "this-is-retarded"
 		ret=$(eval $(
-			sed -n \
+			${SED} -n \
 				-e 's:[[:space:]]::g' \
 				-e "/^${varname}=/p" \
 				"${conf}"
@@ -109,8 +112,8 @@ try_real_hard_to_find_CHOST() {
 	#
 	# Then we try /etc/env.d/gcc/config-${CTARGET}
 	#
-	if [[ -s ${ROOT}/etc/env.d/gcc/config-${CTARGET} ]] ; then
-		ret=$(split_gcc_ver $(show_var CURRENT "${ROOT}"/etc/env.d/gcc/config-${CTARGET}))
+	if [[ -s ${EROOT}/etc/env.d/gcc/config-${CTARGET} ]] ; then
+		ret=$(split_gcc_ver $(show_var CURRENT "${EROOT}"/etc/env.d/gcc/config-${CTARGET}))
 		echo ${ret% *}
 	fi
 }
@@ -124,7 +127,7 @@ get_chost() {
 
 	# make sure portage isnt broken
 	if python -V &>/dev/null ; then
-		CHOST=$(portageq envvar CHOST 2>/dev/null)
+		CHOST=$(env -i EPREFIX="${BPREFIX}" "$(PATH="${BPREFIX}/usr/bin:${PATH}" type -P portageq)" envvar CHOST 2>/dev/null)
 	else
 		ewarn "Python seems to be broken, attempting to locate CHOST ourselves ..."
 		CHOST=$(try_real_hard_to_find_CHOST)
@@ -133,7 +136,7 @@ get_chost() {
 	if [[ -z ${CHOST} ]] ; then
 		eerror "${argv0}: Could not get portage CHOST!"
 		eerror "${argv0}: You should verify that CHOST is set in one of these places:"
-		eerror "${argv0}:  - ${ROOT}/etc/portage/make.conf"
+		eerror "${argv0}:  - ${EROOT}/etc/portage/make.conf"
 		eerror "${argv0}:  - active environment"
 		exit 1
 	fi
@@ -196,7 +199,7 @@ update_wrappers() {
 	# Find the bin wrapper
 	local wrapper
 	for wrapper in ${GENTOO_LIBDIR} lib lib64 lib32 lib ; do
-		wrapper="${ROOT}usr/${wrapper}/misc/gcc-config"
+		wrapper="${EROOT}usr/${wrapper}/misc/gcc-config"
 		[[ -e ${wrapper} ]] && break
 	done
 
@@ -222,7 +225,7 @@ update_wrappers() {
 	# new one does not.
 	for x in "${old_wrappers[@]}" ; do
 		has "${x}" "${new_wrappers[@]}" && continue
-		rm -f "${ROOT}usr/bin/${x}" "${ROOT}usr/bin/${CTARGET}-${x}"
+		rm -f "${EROOT}usr/bin/${x}" "${EROOT}usr/bin/${CTARGET}-${x}"
 	done
 
 	# For all toolchains, we want to create the fully qualified
@@ -259,20 +262,19 @@ update_wrappers() {
 
 		# Now do the actual wrapper copy with paths to the reference binary
 		if [[ -x ${ref} ]] ; then
-			atomic_cp "${wrapper}" "${ROOT}usr/bin" "${x}" "${ref}"
+			atomic_cp "${wrapper}" "${EROOT}usr/bin" "${x}" "${ref}"
 		else
 			ewarn "double insanity with ${x} and ${ref}"
 			# Make sure we have no stale wrappers
-			rm -f "${ROOT}usr/bin/${x}"
+			rm -f "${EROOT}usr/bin/${x}"
 		fi
 	done
 	# legacy cruft, make sure we dont leave it laying around #143205
-	rm -f "${ROOT}usr/bin/${CTARGET}-cc" "${ROOT}usr/bin"/{${CTARGET}-,}g{cc,++}{32,64}
+	rm -f "${EROOT}usr/bin/${CTARGET}-cc" "${EROOT}usr/bin"/{${CTARGET}-,}g{cc,++}{32,64}
 
 	# install the canonical cpp wrapper
-	[[ ${CTARGET} == *-solaris* ]] && return 0
 	if ! is_cross_compiler ; then
-		atomic_cp "${wrapper}" "${ROOT}lib" "cpp" "${ROOT}usr/bin/cpp"
+		atomic_cp "${wrapper}" "${EROOT}lib" "cpp" "${EROOT}usr/bin/cpp"
 	fi
 }
 
@@ -301,33 +303,45 @@ handle_split_usr() {
 	eval $(grep -h '^LDPATH=' "${GCC_ENV_D}"/${CHOST}-* | tail -1)
 	LDPATH=${LDPATH%%:*}
 
-	# If /usr isn't a sep mount, then don't bother with linking stuff.
-	if ln "${ROOT}/${LDPATH}/libgcc.a" "${ROOT}"/lib/.gcc.config.$$ 2>/dev/null ; then
-		rm -f "${ROOT}"/lib/.gcc.config.$$
-		if [[ -n $(find "${ROOT}"/lib*/lib{gcc_s,unwind}.so* 2>/dev/null) ]] ; then
+	# If /usr isn't a sep mount or EPREFIX is set, then don't bother with linking stuff.
+	if [[ -n ${EPREFIX} ]] || ln "${ROOT}/${LDPATH}/libgcc.a" "${EROOT}"/lib/.gcc.config.$$ 2>/dev/null ; then
+		rm -f "${EROOT}"/lib/.gcc.config.$$
+		if [[ -n $(find "${EROOT}"/lib*/lib{gcc_s,unwind}{.so*,*dylib} 2>/dev/null) ]] ; then
 			# If we previously had stuff in /, make sure ldconfig gets re-run.
-			rm -f "${ROOT}"/lib*/lib{gcc_s,unwind}.so*
+			rm -f "${EROOT}"/lib*/lib{gcc_s,unwind}{.so*,*dylib}
 			return 1
 		fi
 		return 0
 	fi
 
-	# Only bother with this stuff for the native ABI.  We assume the user
-	# doesn't have critical binaries for non-native ABIs which is fair.
-	local gcclib
-	local libdir="${ROOT}${GENTOO_LIBDIR}"
-	mkdir -p "${libdir}"/.gcc.config.new || return 0 # !?!?!
-	for gcclib in gcc_s unwind ; do
-		# This assumes that we always have the .so symlink,
-		# but for now, that should be safe ...
-		for gcclib in "${ROOT}${LDPATH}"/lib${gcclib}.so.* ; do
-			[[ -e ${gcclib} ]] || continue
-			cp -pP "${gcclib}" "${libdir}"/.gcc.config.new/
-			# no need to sanity `rm` this as the `mv` should take care
-			# of it.  we also need this step to be completely atomic
-			# for systems that have even `mv` linked against libgcc_s.so.
-			# http://bugs.gentoo.org/150257
-			mv -f "${libdir}"/.gcc.config.new/* "${libdir}"/
+	gcc="${ROOT}${LATEST_GCC_PATH}/gcc"
+
+	local multilib
+	for multilib in $("${gcc}" -print-multi-lib); do
+		local multiarg=${multilib#*;}
+		multiarg=${multiarg/@/-}
+		local multilibdir=${multilib%;*}
+		local libdir="${EROOT}lib/"$("${gcc}" ${multiarg} -print-multi-os-directory)
+
+		mkdir -p "${libdir}"/.gcc.config.new || continue # !?!?!
+
+		# Only bother with this stuff for the native ABI.  We assume the user
+		# doesn't have critical binaries for non-native ABIs which is fair.
+		local gcclib
+		local libdir="${ROOT}${GENTOO_LIBDIR}"
+		mkdir -p "${libdir}"/.gcc.config.new || return 0 # !?!?!
+		for gcclib in gcc_s unwind ; do
+			# This assumes that we always have the .so symlink,
+			# but for now, that should be safe ...
+			for gcclib in "${ROOT}${LDPATH}"/lib${gcclib}.so.* ; do
+				[[ -e ${gcclib} ]] || continue
+				cp -pP "${gcclib}" "${libdir}"/.gcc.config.new/
+				# no need to sanity `rm` this as the `mv` should take care
+				# of it.  we also need this step to be completely atomic
+				# for systems that have even `mv` linked against libgcc_s.so.
+				# http://bugs.gentoo.org/150257
+				mv -f "${libdir}"/.gcc.config.new/* "${libdir}"/
+			done
 		done
 	done
 	rmdir "${libdir}"/.gcc.config.new
@@ -341,7 +355,7 @@ switch_profile() {
 
 	# Make sure we have write access to the dirs.  Do not require `root`
 	# so that we work with prefix/cross/etc... setups that run as user.
-	[[ ! -w ${ROOT} ]] && die "need write access to ${ROOT}"
+	[[ ! -w ${EROOT} ]] && die "need write access to ${EROOT}"
 
 	if is_cross_compiler ; then
 		ebegin "Switching cross-compiler to ${CC_COMP}"
@@ -408,7 +422,7 @@ switch_profile() {
 		# Pass all by default
 		awk '!/^(STDCXX_INCDIR|LDPATH|CC|CXX|CTARGET|GCCBITS|GCC_SPECS|GCC_PATH|MULTIOSDIRS)=/ {print $0}' \
 			"${GCC_ENV_D}/${CC_COMP}" >> "${envd}.tmp"
-		if [[ -d ${ROOT}/etc/ld.so.conf.d ]] ; then
+		if [[ -z ${EPREFIX} && -d ${ROOT}/etc/ld.so.conf.d ]] ; then
 			echo "${MY_LDPATH}" > "${ROOT}"/etc/ld.so.conf.d/05gcc-${CTARGET}.conf
 		else
 			echo "LDPATH=\"${MY_LDPATH}\"" >> "${envd}.tmp"
@@ -427,7 +441,7 @@ switch_profile() {
 		local x libdir pkgconfdir
 		local mver=${CC_COMP_VERSION:0:3}
 		for libdir in ${MULTIOSDIRS//:/ } ; do
-			pkgconfdir="${ROOT}/usr/lib/${libdir}/pkgconfig"
+			pkgconfdir="${EROOT}/usr/lib/${libdir}/pkgconfig"
 			for x in "" "-${mver}" ; do
 				x="${pkgconfdir}/libgcj${x}.pc"
 				if [[ -e ${pkgconfdir}/libgcj-${CC_COMP_VERSION}.pc ]] ; then
@@ -458,7 +472,7 @@ switch_profile() {
 			ewarn "env-update failed to work properly; making sure ld.so.conf paths"
 			ewarn "are setup properly.  Please rerun gcc-config with the -f option."
 			echo ""
-			if [[ ! -d /etc/ld.so.conf.d ]] ; then
+			if [[ -z ${EPREFIX} && ! -d /etc/ld.so.conf.d ]] ; then
 				show_var LDPATH "${ROOT}"/etc/env.d/05gcc-${CTARGET} \
 					| sed -e 's|:|\n|g' >> /etc/ld.so.conf
 			fi
@@ -475,7 +489,9 @@ switch_profile() {
 		ewarn "If you intend to use the gcc from the new profile in an already"
 		ewarn "running shell, please remember to do:"
 		echo
-		ewarn "  . /etc/profile"
+		ewarn " (bash) # . ${EPREFIX}/etc/profile"
+		ewarn "or"
+		ewarn " (tcsh) # source ${EPREFIX}/etc/csh.login"
 		echo
 	fi
 
@@ -653,7 +669,7 @@ DOIT=""
 FORCE="no"
 
 CC_COMP=
-ENV_D="${ROOT}etc/env.d"
+ENV_D="${EROOT}etc/env.d"
 GCC_ENV_D="${ENV_D}/gcc"
 
 for x in "$@" ; do
@@ -784,7 +800,11 @@ if [[ -z ${CC_COMP} ]] ; then
 fi
 
 if [[ ${DOIT} != "get_current_profile" ]] ; then
-	GCC_LIB=$(get_lib_path | awk -F/ '{ print  "/"$2"/"$3"/"$4"/" }')
+	GCC_LIB=$(
+		get_lib_path | \
+ 			sed -e "s|${EPREFIX}/*|/|g" | \
+			awk -F/ '{ print "/"$2"/"$3"/"$4"/" }'
+	)
 
 	# For people who insist on using funky version strings ("4.6.x"
 	# rather than "4.6.2"), allow them to manually specify it.
@@ -797,11 +817,11 @@ if [[ ${DOIT} != "get_current_profile" ]] ; then
 		CC_COMP_TARGET=${CC_COMP%-${CC_COMP_VERSION}*}
 	fi
 
-	if [[ ! -d ${ROOT}/${GCC_LIB}/${CC_COMP_TARGET}/${CC_COMP_VERSION} ]]; then
+	if [[ ! -d ${EROOT}/${GCC_LIB}/${CC_COMP_TARGET}/${CC_COMP_VERSION} ]]; then
 		CC_COMP_VERSION=${CC_COMP_VERSION%-*}
 	fi
 
-	if [[ ! -d ${ROOT}/${GCC_LIB}/${CC_COMP_TARGET}/${CC_COMP_VERSION} ]] || \
+	if [[ ! -d ${EROOT}/${GCC_LIB}/${CC_COMP_TARGET}/${CC_COMP_VERSION} ]] || \
 	   [[ ! -f ${GCC_ENV_D}/${CC_COMP} ]]
 	then
 		eerror "${argv0}: Profile does not exist or invalid setting for ${GCC_ENV_D}/${CC_COMP}" 1>&2
diff --git a/a/wrapper.c.in b/b/wrapper.c.in
index 65e5317..afa03bc 100644
--- a/a/wrapper.c.in
+++ b/b/wrapper.c.in
@@ -21,8 +21,8 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#define GCC_CONFIG "/usr/bin/gcc-config"
-#define ENVD_BASE  "/etc/env.d/05gcc"
+#define GCC_CONFIG "@GENTOO_PORTAGE_EPREFIX@/usr/bin/gcc-config"
+#define ENVD_BASE  "@GENTOO_PORTAGE_EPREFIX@/etc/env.d/05gcc"
 
 #define ARRAY_SIZE(arr) (sizeof(arr)/sizeof(arr[0]))
 
@@ -146,7 +146,7 @@ static int find_target_in_envd(struct wrapper_data *data, int cross_compile)
 		/* for the sake of speed, we'll keep a symlink around for
 		 * the native compiler.  #190260
 		 */
-		snprintf(envd_file, sizeof(envd_file)-1, "/etc/env.d/gcc/.NATIVE");
+		snprintf(envd_file, sizeof(envd_file)-1, "@GENTOO_PORTAGE_EPREFIX@/etc/env.d/gcc/.NATIVE");
 	} else {
 		char *ctarget, *end = strrchr(data->name, '-');
 		if (end == NULL)
@@ -213,7 +213,7 @@ static void find_wrapper_target(struct wrapper_data *data)
 	/* Only our wrapper is in PATH, so get the CC path using
 	 * gcc-config and execute the real binary in there ...
 	 */
-	FILE *inpipe = popen("ROOT= " GCC_CONFIG " --get-bin-path", "r");
+	FILE *inpipe = popen("ROOT= EPREFIX=\"@GENTOO_PORTAGE_EPREFIX@\" " GCC_CONFIG " --get-bin-path", "r");
 	if (inpipe == NULL)
 		wrapper_errp("could not open pipe");
 
@@ -289,8 +289,8 @@ int main(int argc, char *argv[])
 			data.name = wrapper_aliases[i].target;
 
 	/* What is the full name of our wrapper? */
-	data.fullname = xmalloc(strlen(data.name) + sizeof("/usr/bin/") + 1);
-	sprintf(data.fullname, "/usr/bin/%s", data.name);
+	data.fullname = xmalloc(strlen(data.name) + sizeof("@GENTOO_PORTAGE_EPREFIX@/usr/bin/") + 1);
+	sprintf(data.fullname, "@GENTOO_PORTAGE_EPREFIX@/usr/bin/%s", data.name);
 
 	find_wrapper_target(&data);