diff --git a/dev-libs/pkcs11-helper/Manifest b/dev-libs/pkcs11-helper/Manifest
new file mode 100644
index 0000000..30e6d24
--- /dev/null
+++ b/dev-libs/pkcs11-helper/Manifest
@@ -0,0 +1,4 @@
+AUX pkcs11-helper-1.29.0-incompatible-func-ptr-clang16.patch 792 BLAKE2B c0bd5925600a01707bc622916593fbafc784665ee1445b49f6a58212a35730d53301184ef943b4759a0e095b3a7e88b9f728b82d86dc2c0b5a52e2a749547ab9 SHA512 ddc5c9199c5be72c0866ecd3ce6c9300bf6986524968874574f949653efffb350967ab3b559ff494a144d9ecdb25f7b22ec1a7d1ef073b178022beb2a053b0a5
+DIST pkcs11-helper-1.29.0.tar.bz2 422549 BLAKE2B fec72ac82f1545fc50f80b5b28db12906df32fa3bc65f80541d8bee7f1d1c8062f1f0516344237424022c01d4f390e8a72e3e0262250f3b6c51df92c768d81ee SHA512 c530f5a4b5826a02bfe787a1293a7595d5a0d6348daa16675bd10c6d6734b1f24a3cc73b5b89433cf1edf8815f8b7298fdfd1ed686f096bb5edfb425e9430eb2
+EBUILD pkcs11-helper-1.29.0-r1.ebuild 1098 BLAKE2B 11126d3c3d05ee4b8e15c07ab6dfae7eb32fafedac07209aa375c2ff5cd2ca2e23359ae8c43f78a7c5ef9f9373e400d591621103eab9288db9cb9c9980975dd2 SHA512 2bcc131d611685780c3846d601963772c303680c971cae28830e71d4ff686373f26451b8cac6db3f3a872c0954c2dbb58ac1337dc225fddbe38ef72758067678
+MISC metadata.xml 435 BLAKE2B 7740f428a33cecd516c6cfb96de878c8080b2cba0b42c78cc34bac42d128619cf4a42b966aafe30bfc13a045ad0017285ecff9d60d237eadd715fcdf6029c8b8 SHA512 2a9c9d99cfcac14b7c201d5d931f5d1fe0d544328f32db5048a9cd15f0a99ef4016e4b5ec4391500cb5a9e3c00205c72211c61c1fc13cda330faf6b7eb9eeea9
diff --git a/dev-libs/pkcs11-helper/files/pkcs11-helper-1.29.0-incompatible-func-ptr-clang16.patch b/dev-libs/pkcs11-helper/files/pkcs11-helper-1.29.0-incompatible-func-ptr-clang16.patch
new file mode 100644
index 0000000..5b1036b
--- /dev/null
+++ b/dev-libs/pkcs11-helper/files/pkcs11-helper-1.29.0-incompatible-func-ptr-clang16.patch
@@ -0,0 +1,30 @@
+https://github.com/OpenSC/pkcs11-helper/commit/744001c1424b2d178272194d64e3356824ecdcdc
+https://github.com/OpenSC/pkcs11-helper/issues/60
+https://bugs.gentoo.org/880975
+
+From 744001c1424b2d178272194d64e3356824ecdcdc Mon Sep 17 00:00:00 2001
+From: Alon Bar-Lev <alon.barlev@gmail.com>
+Date: Sat, 12 Nov 2022 02:24:58 +0200
+Subject: [PATCH] openssl: fix openssl_ex_data_dup prototype
+
+--- a/lib/pkcs11h-openssl.c
++++ b/lib/pkcs11h-openssl.c
+@@ -340,7 +340,7 @@ int
+ __pkcs11h_openssl_ex_data_dup (
+ 	CRYPTO_EX_DATA *to,
+ 	CRYPTO_EX_DATA *from,
+-	void *from_d,
++	void **from_d,
+ 	int idx,
+ 	long argl,
+ 	void *argp
+@@ -350,7 +350,7 @@ int
+ __pkcs11h_openssl_ex_data_dup (
+ 	CRYPTO_EX_DATA *to,
+ 	const CRYPTO_EX_DATA *from,
+-	void *from_d,
++	void **from_d,
+ 	int idx,
+ 	long argl,
+ 	void *argp
+
diff --git a/dev-libs/pkcs11-helper/metadata.xml b/dev-libs/pkcs11-helper/metadata.xml
new file mode 100644
index 0000000..6af095d
--- /dev/null
+++ b/dev-libs/pkcs11-helper/metadata.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<!-- maintainer-needed -->
+	<use>
+		<flag name="nss">Enable NSS crypto engine</flag>
+	</use>
+	<upstream>
+		<remote-id type="cpe">cpe:/a:opensc-project:opensc</remote-id>
+		<remote-id type="sourceforge">opensc</remote-id>
+		<remote-id type="github">OpenSC/pkcs11-helper</remote-id>
+	</upstream>
+</pkgmetadata>
diff --git a/dev-libs/pkcs11-helper/pkcs11-helper-1.29.0-r1.ebuild b/dev-libs/pkcs11-helper/pkcs11-helper-1.29.0-r1.ebuild
new file mode 100644
index 0000000..390d3cf
--- /dev/null
+++ b/dev-libs/pkcs11-helper/pkcs11-helper-1.29.0-r1.ebuild
@@ -0,0 +1,44 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+DESCRIPTION="PKCS#11 helper library"
+HOMEPAGE="https://github.com/OpenSC/pkcs11-helper"
+SRC_URI="https://github.com/OpenSC/${PN}/releases/download/${P}/${P}.tar.bz2"
+
+LICENSE="|| ( BSD GPL-2 )"
+SLOT="0"
+KEYWORDS="~alpha amd64 arm arm64 ~hppa ~loong ~m68k ~mips ppc ppc64 ~riscv ~s390 ~sparc x86"
+IUSE="doc gnutls nss test"
+# Fails trying to load /usr/lib/pkcs11/provider.so?
+RESTRICT="!test? ( test ) test"
+
+RDEPEND=">=dev-libs/openssl-0.9.7:=
+	gnutls? ( >=net-libs/gnutls-1.4.4:= )
+	nss? ( dev-libs/nss )"
+DEPEND="${RDEPEND}"
+BDEPEND="virtual/pkgconfig
+	doc? ( >=app-text/doxygen-1.4.7 )"
+
+PATCHES=(
+)
+
+src_configure() {
+	econf \
+		--disable-crypto-engine-polarssl \
+		--disable-crypto-engine-mbedtls \
+		$(use_enable doc) \
+		$(use_enable gnutls crypto-engine-gnutls) \
+		$(use_enable nss crypto-engine-nss) \
+		$(use_enable test tests)
+}
+
+src_install() {
+	default
+
+	# bug #555262
+	rm "${ED}"/usr/share/doc/${PF}/COPYING.{BSD,GPL} || die
+
+	find "${ED}" -name '*.la' -delete || die
+}