user/libseccomp: Add

user/libseccomp/APKBUILD

+# Maintainer: Nathan <ndowens@artixlinux.org>
+# Contributor: Natanael Copa <ncopa@alpinelinux.org>
+# Contributor: Carlo Landmeter <clandmeter@gmail.com>
+# Contributor: Dan Williams <dan@ma.ssive.co>
+pkgname=libseccomp
+pkgver=2.5.0
+pkgrel=0
+pkgdesc="An interface to the Linux Kernel's syscall filtering mechanism"
+url="https://github.com/seccomp/libseccomp"
+arch="all"
+license="LGPL-2.1+"
+depends=""
+makedepends="linux-headers gperf"
+checkdepends="bash cmd:which"
+subpackages="$pkgname-dev $pkgname-doc"
+source="https://github.com/seccomp/libseccomp/releases/download/v$pkgver/libseccomp-$pkgver.tar.gz
+	remove-redefinition-prctl.patch
+	"
+
+# secfixes:
+#   2.4.0-r0:
+#     - CVE-2019-9893
+
+build() {
+	./configure \
+		--build=$CBUILD \
+		--host=$CHOST \
+		--prefix=/usr \
+		--sysconfdir=/etc \
+		--mandir=/usr/share/man \
+		--infodir=/usr/share/info \
+		--enable-static \
+		--localstatedir=/var
+	make
+}
+
+check() {
+	make check
+}
+
+package() {
+	make DESTDIR="$pkgdir" install
+}
+
+sha512sums="00ef5aeb4db8dafb546ae680b2d6d9b6aeed008df805d0f28f9dd15c074ff6ea7a5e5131ab503825b8011c59aa23046baedd5849ca040aa73352f43ab2d602ae  libseccomp-2.5.0.tar.gz
+f2c31dcafdc9a1ad78e32e76b75e1c1603071eaa3f979e1f2483b879a34ad07e0a4ef3642196a695415cdf81e1ed2bf325175872fb4e203ef9d0e668c287493f  remove-redefinition-prctl.patch"

user/libseccomp/remove-redefinition-prctl.patch

+--- ./src/system.c.orig
++++ ./src/system.c
+@@ -21,7 +21,6 @@
+ 
+ #include <stdlib.h>
+ #include <errno.h>
+-#include <sys/prctl.h>
+ 
+ #include <seccomp.h>
+