sys-apps/keyutils: Sync with Gentoo

It's from Gentoo commit 6d0c9895fc0f288640588f11ac96c04a7241a95a.

Signed-off-by: Flatcar Buildbot <buildbot@flatcar-linux.org>

sdk_container/src/third_party/portage-stable/sys-apps/keyutils/files/keyutils-1.5.9-header-extern-c.patch

@@ -1,43 +0,0 @@
-sent upstream
-
-From 1f15000ad21c301a51f7746eb561659348060f45 Mon Sep 17 00:00:00 2001
-From: Mike Frysinger <vapier@chromium.org>
-Date: Wed, 25 Jan 2017 14:06:55 -1000
-Subject: [PATCH keyutils] add extern C markings to header file for C++ users
-
-If people try to use keyutils from C++ code, the header doesn't work
-properly because the compiler mangles the keyutils symbols.  Add the
-right extern markings so it works out of the box.
-
-Signed-off-by: Mike Frysinger <vapier@gentoo.org>
----
- keyutils.h | 8 ++++++++
- 1 file changed, 8 insertions(+)
-
-diff --git a/keyutils.h b/keyutils.h
-index a69fa7aaa11d..d50d19d3e929 100644
---- a/keyutils.h
-+++ b/keyutils.h
-@@ -15,6 +15,10 @@
- #include <sys/types.h>
- #include <stdint.h>
- 
-+#ifdef __cplusplus
-+extern "C" {
-+#endif
-+
- extern const char keyutils_version_string[];
- extern const char keyutils_build_string[];
- 
-@@ -180,4 +184,8 @@ extern int recursive_session_key_scan(recursive_key_scanner_t func, void *data);
- extern key_serial_t find_key_by_type_and_desc(const char *type, const char *desc,
- 					      key_serial_t destringid);
- 
-+#ifdef __cplusplus
-+}
-+#endif
-+
- #endif /* KEYUTILS_H */
--- 
-2.11.0
-

sdk_container/src/third_party/portage-stable/sys-apps/keyutils/keyutils-1.6.3-r1.ebuild

@@ -1,4 +1,4 @@
-# Copyright 1999-2025 Gentoo Authors
+# Copyright 1999-2026 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=7
@@ -21,7 +21,6 @@ DEPEND="!prefix? ( >=sys-kernel/linux-headers-2.6.11 )"
 PATCHES=(
 	"${FILESDIR}"/${PN}-1.6-makefile-fixup.patch
 	"${FILESDIR}"/${PN}-1.5.10-disable-tests.patch #519062 #522050
-	"${FILESDIR}"/${PN}-1.5.9-header-extern-c.patch
 	"${FILESDIR}"/${PN}-1.6.3-fix-rpmspec-check.patch
 	"${FILESDIR}"/${PN}-1.6.3-symbols.patch
 	"${FILESDIR}"/${P}-tests.patch