rsyslog: make libyaml support optional via RSYSLOG_libyaml

The upstream rsyslog build links against libyaml-0.so.2 whenever
pkg-config detects yaml-0.1, which made libyaml a hard dependency
of the rsyslog binary without any way to opt out from OpenWrt
config. libyaml is only used for YAML (.yaml/.yml) configuration
files and for loading rate-limiting policies from external files;
RainerScript (.conf) installs do not need it.

Introduce a new RSYSLOG_libyaml Config.in switch, default off, and
gate the +libyaml DEPENDS entry on it. Pass --enable-libyaml or
--disable-libyaml to configure based on the switch.

The upstream configure script in 8.2604.0 does not understand a
--disable-libyaml flag (libyaml was unconditionally autodetected).
Backport upstream commit c5c244861 ("configure: make libyaml
default-on explicit") as 001-configure-make-libyaml-default-on-
explicit.patch, which adds the AC_ARG_ENABLE(libyaml) block. The
patch dissolves cleanly once the package is bumped to 8.2606.0+.
PKG_FIXUP:=autoreconf is added so the configure.ac change flows
into the generated configure script during the SDK build.

Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>

Author: commodo

admin/rsyslog/Config.in

@@ -1,4 +1,12 @@
 if PACKAGE_rsyslog
+	config RSYSLOG_libyaml
+		bool "Enable libyaml support (YAML config + file-based rate-limit policies)"
+		default n
+		help
+		  Enable libyaml support in rsyslog. Required to load YAML
+		  (.yaml/.yml) configuration files and to load rate-limiting
+		  policies from external files. Disable to drop the libyaml
+		  runtime dependency (~50KB).
 	config RSYSLOG_gssapi_krb5
 		bool "Enable GSSAPI Kerberos 5 support"
 		default n

admin/rsyslog/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=rsyslog
 PKG_VERSION:=8.2604.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:= \
@@ -22,6 +22,7 @@ PKG_LICENSE:=GPL-3.0-or-later
 PKG_LICENSE_FILES:=COPYING
 PKG_CPE_ID:=cpe:/a:rsyslog:rsyslog
 
+PKG_FIXUP:=autoreconf
 PKG_INSTALL:=1
 PKG_BUILD_PARALLEL:=1
 
@@ -37,7 +38,7 @@ define Package/rsyslog
 	+RSYSLOG_libdbi:libdbi +libestr +libfastjson +RSYSLOG_gnutls:libgnutls \
 	+RSYSLOG_mmdblookup:libmaxminddb +RSYSLOG_mysql:libmysqlclient \
 	+RSYSLOG_omhttp:libcurl +RSYSLOG_openssl:libopenssl \
-	+RSYSLOG_pgsql:libpq +libuuid +zlib
+	+RSYSLOG_pgsql:libpq +RSYSLOG_libyaml:libyaml +libuuid +zlib
   MENU:=1
 endef
 
@@ -51,6 +52,7 @@ CONFIGURE_ARGS+= \
 	--disable-default-tests \
 	--disable-libsystemd \
 	--disable-impstats-push \
+	$(if $(CONFIG_RSYSLOG_libyaml),--enable-libyaml,--disable-libyaml) \
 	$(if $(CONFIG_RSYSLOG_gssapi_krb5),--enable-gssapi-krb5) \
 	$(if $(CONFIG_RSYSLOG_mysql),--enable-mysql) \
 	$(if $(CONFIG_RSYSLOG_pgsql),--enable-pgsql) \

admin/rsyslog/patches/001-configure-make-libyaml-default-on-explicit.patch

@@ -0,0 +1,58 @@
+From c5c2448617e72d088e818a5581a8a6cc85e81963 Mon Sep 17 00:00:00 2001
+From: Rainer Gerhards <rgerhards@adiscon.com>
+Date: Sat, 16 May 2026 10:44:45 +0200
+Subject: [PATCH] configure: make libyaml default-on explicit
+
+Why: Distro builds must not silently change rsyslog features based
+on whether libyaml development files happen to be installed.
+
+Impact: Default builds now require yaml-0.1 unless --disable-libyaml
+is passed explicitly.
+
+Before/After: Before, configure auto-disabled libyaml features;
+after, the default fails fast and opt-out builds are explicit.
+
+Closes https://github.com/rsyslog/rsyslog/issues/6914
+
+Upstream-Status: Backport [v8.2604.0 -> 8.2606.0]
+Upstream-Commit: c5c2448617e72d088e818a5581a8a6cc85e81963
+---
+ configure.ac | 21 ++++++++++++++++-----
+ 1 file changed, 17 insertions(+), 4 deletions(-)
+
+--- a/configure.ac
++++ b/configure.ac
+@@ -166,13 +166,26 @@
+                  )
+ 
+ # Checks for libraries.
+-PKG_CHECK_MODULES([LIBYAML], [yaml-0.1], [
+-	AC_DEFINE([HAVE_LIBYAML], [1], [Define if libyaml is available])
+-	have_libyaml=yes
+-], [
+-	AC_MSG_WARN([libyaml not found, rate limiting policies from files and YAML configuration support will be disabled])
+-	have_libyaml=no
+-])
++AC_ARG_ENABLE(libyaml,
++	[AS_HELP_STRING([--disable-libyaml],
++		[Disable libyaml-backed YAML configuration and policy file support @<:@default=enabled@:>@])],
++	[case "${enableval}" in
++	 yes) enable_libyaml="yes" ;;
++	  no) enable_libyaml="no" ;;
++	   *) AC_MSG_ERROR(bad value ${enableval} for --enable-libyaml) ;;
++	 esac],
++	[enable_libyaml="yes"]
++)
++AS_IF([test "x$enable_libyaml" = "xyes"], [
++	PKG_CHECK_MODULES([LIBYAML], [yaml-0.1], [
++		AC_DEFINE([HAVE_LIBYAML], [1], [Define if libyaml is available])
++		have_libyaml=yes
++	], [
++		AC_MSG_ERROR([libyaml support is enabled by default but yaml-0.1 was not found. Install libyaml development files or configure with --disable-libyaml.])
++	])
++], [
++	have_libyaml=no
++])
+ AM_CONDITIONAL(HAVE_LIBYAML, test x$have_libyaml = xyes)
+ AC_MSG_NOTICE([YAML configuration support: $have_libyaml])
+ save_LIBS=$LIBS