sys-devel/m4: Sync with Gentoo

It's from Gentoo commit eb58f603e3711cf4b0c1e598b561f8df66891be3.

sdk_container/src/third_party/portage-stable/sys-devel/m4/Manifest

@@ -1,2 +1,3 @@
 DIST m4-1.4.19-test-198-sysval-r1.patch.gz 6292 BLAKE2B 62f52c8bb75e7b8f11e487906f1ce47069ea6d3095fd6532aa6b47bcd8109b7cd733fde26915d449a1cfc326f27f5ed83ba29a5a80687b8b9bdb73c8d87e96b8 SHA512 c3e7d4c1631e401c6b5477c22fd5de837188acf9d72551b116c665a927d1799b1fb249e90c9fb4f6f2f328ee84b2e4dd0bf54f684139997c19ee5b69a3e9284d
 DIST m4-1.4.19.tar.xz 1654908 BLAKE2B 08694485a49c542761fa9a7db4d7609f4dfb08a5c6b785b57f2e14cf1f696c2a1c788bb5eb934e8159a632b63ff071dfe42511d0109d7b1828f46d33c8bf416a SHA512 47f595845c89709727bda0b3fc78e3188ef78ec818965b395532e7041cabe9e49677ee4aca3d042930095a7f8df81de3da1026b23b6897be471f6cf13ddd512b
+DIST m4-1.4.19.tar.xz.sig 488 BLAKE2B 99e89b1ed0bf158d29a652392fb122e23227e895c75a8c63057ebe33f11b433ab205ae99a991578a89df8c3e723fc00669d8cdb290fbc86eaa6c704b112e4370 SHA512 d6ac9c6a54c57e9b53fb3e34a60d49df2f46a6e494da0a0c9ae8246b984e68a853b5d8c42677c1a0485c3f36b0bce10a481d3775c0edc1dbdfb27b43545bc31e

sdk_container/src/third_party/portage-stable/sys-devel/m4/files/loong-fix-build.patch

@@ -0,0 +1,30 @@
+[xen0n: this is https://github.com/sunhaiyong1978/CLFS-for-LoongArch/blob/1.0/patches/stack-direction-add-loongarch.patch with line number tweak, and change to generated file added as well.]
+From: Sun Haiyong <youbest@sina.com>
+Date: Tue, 31 Aug 2021 11:11:52 +0800
+Subject: [PATCH] stack-direction: Add support for loongarch CPU
+
+* m4/stack-direction.m4 (SV_STACK_DIRECTION): When the CPU is loongarch,
+set "sv_cv_stack_direction" to "-1" .
+--- a/m4/stack-direction.m4
++++ b/m4/stack-direction.m4
+@@ -31,6 +31,7 @@ AC_DEFUN([SV_STACK_DIRECTION],
+       i?86 | x86_64 | \
+       i860 | \
+       ia64 | \
++      loongarch* | \
+       m32r | \
+       m68* | \
+       m88k | \
+--- a/configure
++++ b/configure
+@@ -46399,6 +46399,7 @@ else $as_nop
+       i?86 | x86_64 | \
+       i860 | \
+       ia64 | \
++      loongarch* | \
+       m32r | \
+       m68* | \
+       m88k | \
+-- 
+2.17.2
+

sdk_container/src/third_party/portage-stable/sys-devel/m4/files/ppc-musl.patch

@@ -1,7 +1,8 @@
-Needed to fix build on ppc + musl. Doesn't seem to yet be in upstream gnulib.
+Needed to fix build on ppc + musl. Should pop up in next gnulib sync in release (different patch).
 
 https://www.openwall.com/lists/musl/2017/11/05/2
 https://github.com/void-linux/void-packages/blob/master/srcpkgs/grep/patches/ppc-musl.patch
+https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=2d830e4a792fcd9f614ed08a7f18584b8b21d23b
 --- a/lib/sigsegv.c
 +++ b/lib/sigsegv.c
 @@ -221,8 +221,10 @@ int libsigsegv_version = LIBSIGSEGV_VERSION;

sdk_container/src/third_party/portage-stable/sys-devel/m4/m4-1.4.19.ebuild

@@ -3,17 +3,21 @@
 
 EAPI=7
 
+VERIFY_SIG_OPENPGP_KEY_PATH="${BROOT}"/usr/share/openpgp-keys/m4.asc
+inherit verify-sig
+
 DESCRIPTION="GNU macro processor"
 HOMEPAGE="https://www.gnu.org/software/m4/m4.html"
-if [[ "${PV}" == *_beta* ]] ; then
+if [[ ${PV} == *_beta* ]] ; then
 	MY_P="${PN}-1.4.18d"
-	#SRC_URI="mirror://gnu-alpha/${PN}/${MY_P}.tar.xz"
 	SRC_URI="https://alpha.gnu.org/gnu/${PN}/${MY_P}.tar.xz"
+	SRC_URI+=" verify-sig? ( https://alpha.gnu.org/gnu/${PN}/${MY_P}.tar.xz.sig )"
 	S="${WORKDIR}/${MY_P}"
 else
 	SRC_URI="mirror://gnu/${PN}/${P}.tar.xz"
 	SRC_URI+=" https://dev.gentoo.org/~floppym/dist/${P}-test-198-sysval-r1.patch.gz"
-	KEYWORDS="~alpha amd64 arm arm64 hppa ~ia64 ~m68k ~mips ppc ppc64 ~riscv ~s390 sparc x86 ~x64-cygwin ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
+	SRC_URI+=" verify-sig? ( mirror://gnu/${PN}/${P}.tar.xz.sig )"
+	KEYWORDS="~alpha amd64 arm arm64 hppa ~ia64 ~loong ~m68k ~mips ppc ppc64 ~riscv ~s390 sparc x86 ~x64-cygwin ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
 fi
 
 LICENSE="GPL-3"
@@ -29,13 +33,34 @@ RDEPEND="
 DEPEND="${RDEPEND}"
 # Remember: cannot dep on autoconf since it needs us
 BDEPEND="app-arch/xz-utils
-	nls? ( sys-devel/gettext )"
+	nls? ( sys-devel/gettext )
+	verify-sig? ( sec-keys/openpgp-keys-m4 )"
 
 PATCHES=(
 	"${FILESDIR}"/ppc-musl.patch
+	"${FILESDIR}"/loong-fix-build.patch
 	"${WORKDIR}"/${P}-test-198-sysval-r1.patch
 )
 
+src_unpack() {
+	if use verify-sig ; then
+		# Needed for downloaded patch (which is unsigned, which is fine)
+		verify-sig_verify_detached "${DISTDIR}"/${P}.tar.xz{,.sig}
+	fi
+
+	default
+}
+
+src_prepare() {
+	default
+
+	# touch generated files after patching m4, to avoid activating maintainer
+	# mode
+	# remove when loong-fix-build.patch is no longer necessary
+	touch ./aclocal.m4 ./lib/config.hin ./configure ./doc/stamp-vti || die
+	find . -name Makefile.in -exec touch {} + || die
+}
+
 src_configure() {
 	local -a myeconfargs=(
 		--enable-changeword