diff --git a/sdk_container/src/third_party/portage-stable/eclass/toolchain.eclass b/sdk_container/src/third_party/portage-stable/eclass/toolchain.eclass
index 2bed15110e..ea223984de 100644
--- a/sdk_container/src/third_party/portage-stable/eclass/toolchain.eclass
+++ b/sdk_container/src/third_party/portage-stable/eclass/toolchain.eclass
@@ -277,6 +277,9 @@ if [[ ${PN} != kgcc64 && ${PN} != gcc-* ]] ; then
 	tc_version_is_at_least 10 && IUSE+=" zstd" TC_FEATURES+=( zstd )
 	tc_version_is_at_least 11 && IUSE+=" valgrind" TC_FEATURES+=( valgrind )
 	tc_version_is_at_least 11 && IUSE+=" custom-cflags"
+	tc_version_is_at_least 12 && IUSE+=" ieee-long-double"
+	tc_version_is_at_least 12.2.1_p20221203 ${PV} && IUSE+=" default-znow"
+	tc_version_is_at_least 12.2.1_p20221203 ${PV} && IUSE+=" default-stack-clash-protection"
 fi
 
 if tc_version_is_at_least 10; then
@@ -289,7 +292,8 @@ fi
 
 #---->> DEPEND <<----
 
-RDEPEND="sys-libs/zlib
+RDEPEND="
+	sys-libs/zlib
 	virtual/libiconv
 	nls? ( virtual/libintl )
 "
@@ -320,7 +324,8 @@ BDEPEND="
 	test? (
 		>=dev-util/dejagnu-1.4.4
 		>=sys-devel/autogen-5.5.4
-	)"
+	)
+"
 DEPEND="${RDEPEND}"
 
 if [[ ${PN} == gcc && ${PV} == *_p* ]] ; then
@@ -798,8 +803,18 @@ make_gcc_hard() {
 		if _tc_use_if_iuse ssp ; then
 			einfo "Updating gcc to use automatic SSP building ..."
 		fi
+		if _tc_use_if_iuse default-stack-clash-protection ; then
+			# The define DEF_GENTOO_SCP is checked in 24_all_DEF_GENTOO_SCP-fstack-clash-protection.patch
+			einfo "Updating gcc to use automatic stack clash protection ..."
+			gcc_hard_flags+=" -DDEF_GENTOO_SCP"
+		fi
+		if _tc_use_if_iuse default-znow ; then
+			# The define DEF_GENTOO_ZNOW is checked in 23_all_DEF_GENTOO_ZNOW-z-now.patch
+			einfo "Updating gcc to request symbol resolution at start (-z now) ..."
+			gcc_hard_flags+=" -DDEF_GENTOO_ZNOW"
+		fi
 		if _tc_use_if_iuse hardened ; then
-			# Will add some hardened options as default, like:
+			# Will add some hardened options as default, e.g. for gcc-12
 			# * -fstack-clash-protection
 			# * -z now
 			# See gcc *_all_extra-options.patch patches.
@@ -1312,6 +1327,13 @@ toolchain_src_configure() {
 			# - bug #704784
 			# - https://gcc.gnu.org/PR93157
 			[[ ${CTARGET} == powerpc64-*-musl ]] && confgcc+=( --with-abi=elfv2 )
+
+			if in_iuse ieee-long-double; then
+				# musl requires 64-bit long double, not IBM double-double or IEEE quad.
+				if [[ ${CTARGET} == powerpc64le-*-gnu ]]; then
+					use ieee-long-double && confgcc+=( --with-long-double-format=ieee )
+				fi
+			fi
 			;;
 		riscv)
 			# Add --with-abi flags to set default ABI