lttng-tools: fix compile failed with libxml2 2.14.0+

Description:
| In file included from /srv/pokybuild/yocto-worker/qemux86-alt/build/build/tmp/work/core2-32-poky-linux/lttng-tools/2.13.15/recipe-sysroot/usr/include/libxml2/libxml/parser.h:25,
|                  from ../../../../lttng-tools-2.13.15/src/common/config/session-config.c:29:
| /srv/pokybuild/yocto-worker/qemux86-alt/build/build/tmp/work/core2-32-poky-linux/lttng-tools/2.13.15/recipe-sysroot/usr/include/libxml2/libxml/encoding.h:173:7: note: declared here
|   173 |     } input XML_DEPRECATED_MEMBER;
|       |       ^~~~~
| ../../../../lttng-tools-2.13.15/src/common/config/session-config.c:432:15: error: called object is not a function or function pointer
|   432 |         ret = handler->input(out_str, &out_len, (const xmlChar *) in_str, &in_len);
|       |               ^~~~~~~
| At top level:
| cc1: note: unrecognized command-line option '-Wno-incomplete-setjmp-declaration' may have been intended to silence earlier diagnostics

According to [1][2], the UTF-8 handler is
```
static xmlCharEncError
UTF8ToUTF8(void *vctxt ATTRIBUTE_UNUSED,
           unsigned char* out, int *outlen,
           const unsigned char* in, int *inlen,
           int flush ATTRIBUTE_UNUSED)
```

Update input.func with setting ATTRIBUTE_UNUSED params with NULL and 0

[1] https://gitlab.gnome.org/GNOME/libxml2/-/commit/38f475072aefe032fff1dc058df3e56c1e7062fa
[2] https://gitlab.gnome.org/GNOME/libxml2/-/commit/69b83bb68e2a8ed0013f80c51b9a358714b00c9a#478024cc18a2cc8dbaed34076e9775f6827f413d_2188_2201

(From OE-Core rev: 5feba5682a0d07de94f4b13d7ef24d537c624cf4)

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 56 insertions, 0 deletions

diff --git a/meta/recipes-kernel/lttng/lttng-tools/0001-fix-lttng-tools-fails-to-compile-with-libxml2-2.14.0.patch b/meta/recipes-kernel/lttng/lttng-tools/0001-fix-lttng-tools-fails-to-compile-with-libxml2-2.14.0.patch
new file mode 100644
index 0000000000..7c2b893731
--- /dev/null
+++ b/meta/recipes-kernel/lttng/lttng-tools/0001-fix-lttng-tools-fails-to-compile-with-libxml2-2.14.0.patch
@@ -0,0 +1,55 @@
+From 0b19e10a8a52fab0bfadbac5ce70f1b2d185a1d1 Mon Sep 17 00:00:00 2001
+From: Hongxu Jia <hongxu.jia@windriver.com>
+Date: Wed, 21 May 2025 13:09:25 +0800
+Subject: [PATCH] fix lttng-tools fails to compile with libxml2 2.14.0+
+
+Description:
+| In file included from /srv/pokybuild/yocto-worker/qemux86-alt/build/build/tmp/work/core2-32-poky-linux/lttng-tools/2.13.15/recipe-sysroot/usr/include/libxml2/libxml/parser.h:25,
+|                  from ../../../../lttng-tools-2.13.15/src/common/config/session-config.c:29:
+| /srv/pokybuild/yocto-worker/qemux86-alt/build/build/tmp/work/core2-32-poky-linux/lttng-tools/2.13.15/recipe-sysroot/usr/include/libxml2/libxml/encoding.h:173:7: note: declared here
+|   173 |     } input XML_DEPRECATED_MEMBER;
+|       |       ^~~~~
+| ../../../../lttng-tools-2.13.15/src/common/config/session-config.c:432:15: error: called object is not a function or function pointer
+|   432 |         ret = handler->input(out_str, &out_len, (const xmlChar *) in_str, &in_len);
+|       |               ^~~~~~~
+| At top level:
+| cc1: note: unrecognized command-line option '-Wno-incomplete-setjmp-declaration' may have been intended to silence earlier diagnostics
+
+
+According to [1][2], the UTF-8 handler is
+```
+static xmlCharEncError
+UTF8ToUTF8(void *vctxt ATTRIBUTE_UNUSED,
+           unsigned char* out, int *outlen,
+           const unsigned char* in, int *inlen,
+           int flush ATTRIBUTE_UNUSED)
+```
+
+Update input.func with setting ATTRIBUTE_UNUSED params with NULL and 0
+
+[1] https://gitlab.gnome.org/GNOME/libxml2/-/commit/38f475072aefe032fff1dc058df3e56c1e7062fa
+[2] https://gitlab.gnome.org/GNOME/libxml2/-/commit/69b83bb68e2a8ed0013f80c51b9a358714b00c9a#478024cc18a2cc8dbaed34076e9775f6827f413d_2188_2201
+
+Upstream-Status: Submitted [https://github.com/lttng/lttng-tools/pull/170]
+Signed-off-by: Marko, Peter <Peter.Marko@siemens.com>
+Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
+---
+ src/common/config/session-config.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/common/config/session-config.c b/src/common/config/session-config.c
+index bb4e9fe..4042d34 100644
+--- a/src/common/config/session-config.c
++++ b/src/common/config/session-config.c
+@@ -429,7 +429,7 @@ static xmlChar *encode_string(const char *in_str)
+                goto end;
+        }
+ 
+-       ret = handler->input(out_str, &out_len, (const xmlChar *) in_str, &in_len);
++       ret = handler->input.func(NULL, out_str, &out_len, (const xmlChar *) in_str, &in_len, 0);
+        if (ret < 0) {
+                xmlFree(out_str);
+                out_str = NULL;
+-- 
+2.34.1
+
diff --git a/meta/recipes-kernel/lttng/lttng-tools_2.13.15.bb b/meta/recipes-kernel/lttng/lttng-tools_2.13.15.bb
index 762d4e5c2f..f39404afa0 100644
--- a/meta/recipes-kernel/lttng/lttng-tools_2.13.15.bb
+++ b/meta/recipes-kernel/lttng/lttng-tools_2.13.15.bb
@@ -39,6 +39,7 @@ SRC_URI = "https://lttng.org/files/lttng-tools/lttng-tools-${PV}.tar.bz2 \
            file://0001-compat-Define-off64_t-as-off_t-on-linux.patch \
            file://0001-tests-add-check_skip_kernel_test-to-check-root-user-.patch \
            file://0001-Fix-rotation-destroy-flush-fix-session-daemon-abort-.patch \
+           file://0001-fix-lttng-tools-fails-to-compile-with-libxml2-2.14.0.patch \
            "
 
 SRC_URI[sha256sum] = "96ea42351ee112c19dad9fdc7aae93b583d9f1722b2175664a381d2d337703c4"