--- toolchain.eclass
+++ toolchain.eclass
@@ -81,7 +81,7 @@
 
 
 #---->> SLOT+IUSE logic <<----
-IUSE="build multislot nls nptl test vanilla"
+IUSE="build nls nptl test vanilla"
 
 if [[ ${PN} != "kgcc64" && ${PN} != gcc-* ]] ; then
 	IUSE+=" altivec cxx fortran nocxx"
@@ -104,7 +104,7 @@
 fi
 
 # Support upgrade paths here or people get pissed
-if use multislot ; then
+if [[ -n ${TOOLCHAIN_MULTISLOT} ]] ; then
 	SLOT="${CTARGET}-${GCC_CONFIG_VER}"
 elif is_crosscompile; then
 	SLOT="${CTARGET}-${GCC_BRANCH_VER}"
@@ -740,7 +740,7 @@
 		ewarn "and this problem has been corrected in >=sys-devel/gcc-config-1.3.10-r1."
 	fi
 
-	if ! is_crosscompile && ! use multislot && [[ ${GCCMAJOR}.${GCCMINOR} == 3.4 ]] ; then
+	if ! is_crosscompile && [[ -z ${TOOLCHAIN_MULTISLOT} ]] && [[ ${GCCMAJOR}.${GCCMINOR} == 3.4 ]] ; then
 		echo
 		ewarn "You should make sure to rebuild all your C++ packages when"
 		ewarn "upgrading between different versions of gcc.	 For example,"
@@ -2048,7 +2048,7 @@
 
 	# If we're using multislot, just run gcc-config if we're installing
 	# to the same profile as the current one.
-	use multislot && return $([[ ${curr_config_ver} == ${GCC_CONFIG_VER} ]])
+	[[ -n ${TOOLCHAIN_MULTISLOT} ]] && return $([[ ${curr_config_ver} == ${GCC_CONFIG_VER} ]])
 
 	if [[ ${curr_branch_ver} == ${GCC_BRANCH_VER} ]] ; then
 		return 0
--- toolchain-binutils.eclass
+++ toolchain-binutils.eclass
@@ -77,11 +77,11 @@
 else
 	LICENSE="|| ( GPL-2 LGPL-2 )"
 fi
-IUSE="nls multitarget multislot static-libs test vanilla"
+IUSE="nls multitarget static-libs test vanilla"
 if version_is_at_least 2.19 ; then
 	IUSE+=" zlib"
 fi
-if use multislot ; then
+if [[ -n ${TOOLCHAIN_MULTISLOT} ]] ; then
 	SLOT="${CTARGET}-${BVER}"
 elif is_cross ; then
 	SLOT="${CTARGET}"