diff --git a/sys-devel/clang/clang-9999.ebuild b/sys-devel/clang/clang-9999.ebuild
index aa1e71c..98268ec 100644
--- a/sys-devel/clang/clang-9999.ebuild
+++ b/sys-devel/clang/clang-9999.ebuild
@@ -14,13 +14,14 @@ SRC_URI=""
 ESVN_REPO_URI="http://llvm.org/svn/llvm-project/cfe/trunk"
 
 LICENSE="UoI-NCSA"
-SLOT="0"
+SLOT="${PV}"
 KEYWORDS=""
 IUSE="debug multitarget python +static-analyzer test"
 
 DEPEND="static-analyzer? ( dev-lang/perl )
 	${PYTHON_DEPS}"
 RDEPEND="~sys-devel/llvm-${PV}[debug=,multitarget=]
+	app-admin/eselect-clang
 	${PYTHON_DEPS}"
 
 S="${WORKDIR}/llvm"
@@ -51,7 +52,7 @@ src_prepare() {
 		-i tools/clang/tools/scan-build/scan-build \
 		|| die "scan-build sed failed"
 	# Set correct path for gold plugin
-	sed -e "/LLVMgold.so/s#lib/#$(get_libdir)/llvm/#" \
+	sed -e "/LLVMgold.so/s#lib/#$(get_libdir)/llvm-${SLOT}/#" \
 		-i  tools/clang/lib/Driver/Tools.cpp \
 		|| die "gold plugin path sed failed"
 
@@ -63,7 +64,7 @@ src_prepare() {
 		-i Makefile.config.in || die "Makefile.config sed failed"
 
 	einfo "Fixing rpath and CFLAGS"
-	sed -e 's,\$(RPATH) -Wl\,\$(\(ToolDir\|LibDir\)),$(RPATH) -Wl\,'"${EPREFIX}"/usr/$(get_libdir)/llvm, \
+	sed -e "s@\$(RPATH) -Wl,'\$\$ORIGIN/../lib'@\$(RPATH) -Wl,'${EPREFIX}/usr/$(get_libdir)/llvm-${SLOT}'@" \
 		-e '/OmitFramePointer/s/-fomit-frame-pointer//' \
 		-i Makefile.rules || die "rpath sed failed"
 
@@ -135,11 +136,86 @@ src_install() {
 		doins tools/scan-build/sorttable.js
 	fi
 
+	# Register slot for app-admin/eselect-clang
+	local eselect_dir="/usr/share/eselect-clang/slots/${SLOT}"
+	dodir "${eselect_dir}"
+	eselect_dir="${ED}/${eselect_dir}"
+	echo "${CATEGORY}/${PF}" > "${eselect_dir}/ebuild"
+
+	with_slot_suffix() {
+		local file=$(echo "$1" | sed -e "s/-${SLOT}//")
+		local ext=""
+		if [[ "${file}" =~ \. ]] ; then
+			ext=".${file#*.}"
+		fi
+		local base="${file%%.*}"
+		echo "${base}-${SLOT}${ext}"
+	}
+
+	make_versioned() {
+		local dir=$1
+		local candidates=(${ED%/}/${dir})
+		if [[ ! ${dir##*/} ]] ; then
+			dir=${dir%/}
+			candidates=( "${candidates}"* )
+		else
+			dir=$(dirname "${dir}")
+		fi
+
+		pushd ${ED%/}/${dir} >/dev/null || die
+
+		local candidate
+		for candidate in "${candidates[@]}" ; do
+			if [[ -h "${candidate}" ]] ; then
+				# Add slot suffix to symlink target
+				local target=$(readlink -s "${candidate}")
+				local slotted_target=$(with_slot_suffix "${target}")
+				if [[ -e "${target}" ]] || [[ -e "${slotted_target}" ]] ; then
+					ln -sf "${slotted_target}" "${candidate}" \
+						|| die "Could not update symlink"
+				fi
+			fi
+
+			local base_name=$(basename "${candidate}")
+			local slotted_name=$(with_slot_suffix "${base_name}")
+			mv "${candidate}" "${ED}/${dir}/${slotted_name}" \
+				|| die "Could not rename ${candidate} to ${slotted_name}"
+			echo "/${dir#/}/${base_name}" >> "${eselect_dir}/versioned"
+		done
+
+		popd >/dev/null || die
+	}
+
+	# Trailing slash => version the content
+	# No trailing slash => version the directory itself
+	local paths=(
+		/usr/bin/
+		/usr/$(get_libdir)/llvm
+		/usr/include/
+		/usr/share/clang
+		/usr/share/man/man1/
+	)
+
+	local path
+	for path in "${paths[@]}" ; do
+		make_versioned "${path}"
+	done
+
+	python_doscript_versioned() {
+		local path="$1"
+		local file=$(basename "${path}")
+
+		python_newscript "${path}" $(with_slot_suffix "${file}")
+
+		local scriptroot=${python_scriptroot:-${DESTTREE%/}/bin}
+		echo "${scriptroot%/}/${file}" >> "${eselect_dir}/versioned"
+	}
+
 	python_inst() {
 		if use static-analyzer ; then
 			pushd tools/scan-view >/dev/null || die
 
-			python_doscript scan-view
+			python_doscript_versioned scan-view
 
 			touch __init__.py || die
 			python_moduleinto clang
@@ -157,8 +233,11 @@ src_install() {
 			popd >/dev/null || die
 		fi
 
+		use static-analyzer || use python && \
+			make_versioned "$(python_get_sitedir)/clang"
+
 		# AddressSanitizer symbolizer (currently separate)
-		python_doscript "${S}"/projects/compiler-rt/lib/asan/scripts/asan_symbolize.py
+		python_doscript_versioned "${S}"/projects/compiler-rt/lib/asan/scripts/asan_symbolize.py
 	}
 	python_foreach_impl python_inst
 
@@ -167,21 +246,39 @@ src_install() {
 	if [[ ${CHOST} == *-darwin* ]] ; then
 		for lib in libclang.dylib ; do
 			ebegin "fixing install_name of $lib"
-			install_name_tool -id "${EPREFIX}"/usr/lib/llvm/${lib} \
-				"${ED}"/usr/lib/llvm/${lib}
+			install_name_tool -id "${EPREFIX}"/usr/lib/llvm-${SLOT}/${lib} \
+				"${ED}"/usr/lib/llvm-${SLOT}/${lib}
 			eend $?
 		done
-		for f in usr/bin/{c-index-test,clang} usr/lib/llvm/libclang.dylib ; do
+		for f in usr/bin/{c-index-test,clang} usr/lib/llvm-${SLOT}/libclang.dylib ; do
 			ebegin "fixing references in ${f##*/}"
 			install_name_tool \
 				-change "@rpath/libclang.dylib" \
-					"${EPREFIX}"/usr/lib/llvm/libclang.dylib \
+					"${EPREFIX}"/usr/lib/llvm-${SLOT}/libclang.dylib \
 				-change "@executable_path/../lib/libLLVM-${PV}.dylib" \
-					"${EPREFIX}"/usr/lib/llvm/libLLVM-${PV}.dylib \
+					"${EPREFIX}"/usr/lib/llvm-${SLOT}/libLLVM-${PV}.dylib \
 				-change "${S}"/Release/lib/libclang.dylib \
-					"${EPREFIX}"/usr/lib/llvm/libclang.dylib \
+					"${EPREFIX}"/usr/lib/llvm-${SLOT}/libclang.dylib \
 				"${ED}"/$f
 			eend $?
 		done
 	fi
 }
+
+pkg_postinst() {
+	if [[ $(eselect ${PN} show) = "(none)" ]] ; then
+		eselect ${PN} set ${SLOT}
+	fi
+}
+
+pkg_prerm() {
+	if [[ $(eselect ${PN} show) = ${SLOT} ]] ; then
+		eselect ${PN} clear
+	fi
+}
+
+pkg_postrm() {
+	if [[ -z ${REPLACED_BY_VERSION} ]] ; then
+		eselect ${PN} update
+	fi
+}