eclass/toolchain-autoconf: Sync with Gentoo

It's from Gentoo commit 8839833a322cc2776225c20de422b38540a5d27f.

sdk_container/src/third_party/portage-stable/eclass/toolchain-autoconf.eclass

@@ -1,29 +1,36 @@
-# Copyright 1999-2019 Gentoo Authors
+# Copyright 1999-2023 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # @ECLASS: toolchain-autoconf.eclass
 # @MAINTAINER:
 # <base-system@gentoo.org>
-# @SUPPORTED_EAPIS: 6 7
+# @SUPPORTED_EAPIS: 7 8
 # @BLURB: Common code for sys-devel/autoconf ebuilds
 # @DESCRIPTION:
 # This eclass contains the common phase functions migrated from
 # sys-devel/autoconf eblits.
 
-case ${EAPI:-0} in
+case ${EAPI} in
-	[0-5])
+	7|8) ;;
-		die "${ECLASS} is banned in EAPI ${EAPI:-0}"
+	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
-		;;
-	[6-7])
-		;;
-	*)
-		die "Unknown EAPI ${EAPI:-0}"
-		;;
 esac
 
 if [[ -z ${_TOOLCHAIN_AUTOCONF_ECLASS} ]]; then
+_TOOLCHAIN_AUTOCONF_ECLASS=1
 
-EXPORT_FUNCTIONS src_prepare src_configure src_install
+# @ECLASS_VARIABLE: TC_AUTOCONF_BREAK_INFOS
+# @DESCRIPTION:
+# Enables slotting logic on the installed info pages.  This includes
+# mangling the pages in order to include a version number.  Empty by
+# default, and only exists for old ebuild revisions to use.  Do not set
+# in new ebuilds.  Set to a non-empty value to enable.
+# @DEPRECATED: none
+: "${TC_AUTOCONF_BREAK_INFOS:=}"
+
+# @ECLASS_VARIABLE: TC_AUTOCONF_INFOPATH
+# @DESCRIPTION:
+# Where to install info files if not slotting.
+TC_AUTOCONF_INFOPATH="${EPREFIX}/usr/share/autoconf-${PV}/info"
 
 toolchain-autoconf_src_prepare() {
 	find -name Makefile.in -exec sed -i '/^pkgdatadir/s:$:-@VERSION@:' {} + || die
@@ -33,7 +40,15 @@ toolchain-autoconf_src_prepare() {
 toolchain-autoconf_src_configure() {
 	# Disable Emacs in the build system since it is in a separate package.
 	export EMACS=no
-	econf --program-suffix="-${PV}" || die
+	local myconf=(
+		--program-suffix="-${PV}"
+	)
+	if [[ -z "${TC_AUTOCONF_BREAK_INFOS}" && "${SLOT}" != 0 ]]; then
+		myconf+=(
+			--infodir="${TC_AUTOCONF_INFOPATH}"
+		)
+	fi
+	econf "${myconf[@]}" || die
 	# econf updates config.{sub,guess} which forces the manpages
 	# to be regenerated which we dont want to do #146621
 	touch man/*.1
@@ -72,8 +87,27 @@ slot_info_pages() {
 
 toolchain-autoconf_src_install() {
 	default
+	if [[ -n "${TC_AUTOCONF_BREAK_INFOS}" ]]; then
 		slot_info_pages
+	else
+		rm -f dir || die
+
+		local major="$(ver_cut 1)"
+		local minor="$(ver_cut 2)"
+		local idx="$((99999-(major*1000+minor)))"
+		newenvd - "06autoconf${idx}" <<-EOF
+		INFOPATH="${TC_AUTOCONF_INFOPATH}"
+		EOF
+
+		pushd "${D}/${TC_AUTOCONF_INFOPATH}" >/dev/null || die
+		for f in *.info*; do
+			# Install convenience aliases for versioned Autoconf pages.
+			ln -s "$f" "${f/./-${PV}.}" || die
+		done
+		popd >/dev/null || die
+	fi
 }
 
-_TOOLCHAIN_AUTOCONF_ECLASS=1
 fi
+
+EXPORT_FUNCTIONS src_prepare src_configure src_install