sys-libs/libseccomp: fix build on loong; keyword 2.5.4 for ~loong

The LoongArch patch is generated by diffing the original release
tarball with the dist tarball, made with the LoongArch support
PR [1] applied. Tests have passed on amd64 and loong.

[1]: seccomp/libseccomp#356

See: gentoo#25189
Signed-off-by: WANG Xuerui <xen0n@gentoo.org>

sys-libs/libseccomp/Manifest

@@ -1,3 +1,4 @@
 DIST libseccomp-2.5.1.tar.gz 638811 BLAKE2B 683ae7536c0cba36f4d30640b42361171fc34b7cb04985ea56e64369df29c440361a0205385b14580cc0e481e0f9ffd0b0e8ebd4ac98817ed59298db6b274c35 SHA512 2be80a6323f9282dbeae8791724e5778b32e2382b2a3d1b0f77366371ec4072ea28128204f675cce101c091c0420d12c497e1a9ccbb7dc5bcbf61bfd777160af
 DIST libseccomp-2.5.3.tar.gz 637572 BLAKE2B cedf04b3a926f9fe5202e6169ddac6b983e755009c14fc1d645157b9c0bcdf65d4085f8ea7abad90f3a0c13ae4d66b5d8306e725168490863aad15976de1eae7 SHA512 00170fe2360f0c0b33293dccfcc33e98fabb99619f34ecefbcc92bfdaa249ba91e7433226545b842b71542a3b224b6e980ea2ae656c4addf07e84a0def1870a0
+DIST libseccomp-2.5.4-loongarch64-20220425.patch.xz 132768 BLAKE2B f3ab165b028b5f8b4c16574936b915595807ebeb49ef7365d6051f3dfafa7da46ef2a9de458e0a268298cb340152abe1f3c0c293446462a06696bc9ce92d2f72 SHA512 94f23c7a2cc2ea8acb01fef00ef184295c276b14b2b3ba0c65687fd72081df8478f3f04c51b0b391ba44529c4f914e6edbb4132af935e3be55902f641d478780
 DIST libseccomp-2.5.4.tar.gz 637228 BLAKE2B 38b134cb578f9355667546f92950ebcf8c53ccaf98db568db9aadfa9629c054136849e03d4bf9f09f73998fe66a5e8a9038573d19740b2bddf5518a8a0119229 SHA512 92650bd7d1d48b383f402a536b97a017fd0f6ad1234daf4b938d01c92e8d134a01d2f2dd45fd9e2d025d7556bd1386ec360402145a87f20580c85949d62cea0e

sys-libs/libseccomp/libseccomp-2.5.4.ebuild

@@ -16,8 +16,9 @@ if [[ ${PV} == *9999 ]] ; then
 	PRERELEASE="2.6.0"
 	inherit autotools git-r3
 else
-	SRC_URI="https://github.com/seccomp/libseccomp/releases/download/v${PV}/${P}.tar.gz"
-	KEYWORDS="-* ~amd64 ~arm ~arm64 ~hppa ~mips ~ppc ~ppc64 ~riscv ~s390 ~x86 ~amd64-linux ~x86-linux"
+	SRC_URI="https://github.com/seccomp/libseccomp/releases/download/v${PV}/${P}.tar.gz
+		https://dev.gentoo.org/~xen0n/distfiles/${P}-loongarch64-20220425.patch.xz"
+	KEYWORDS="-* ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~x86 ~amd64-linux ~x86-linux"
 fi
 
 LICENSE="LGPL-2.1"
@@ -39,6 +40,7 @@ BDEPEND="${DEPEND}
 PATCHES=(
 	"${FILESDIR}"/libseccomp-python-shared.patch
 	"${FILESDIR}"/libseccomp-2.5.3-skip-valgrind.patch
+	"${WORKDIR}"/libseccomp-2.5.4-loongarch64-20220425.patch
 )
 
 src_prepare() {