https://github.com/ceph/ceph/pull/66924

From 8cf106cc799e641d51ab56cbf23903d9c994f924 Mon Sep 17 00:00:00 2001
From: "Z. Liu" <zhixu.liu@gmail.com>
Date: Wed, 14 Jan 2026 12:08:53 +0800
Subject: [PATCH] CMakeLists.txt: add option to build agains system
 opentelemetry

In Gentoo, if build against system opentelemetry, cmake failed with:

> CMake Error at src/CMakeLists.txt:443 (target_link_libraries):
>   The link interface of target "jaeger_base" contains:
>
>     opentelemetry::libopentelemetry
>
>   but the target was not found.  Possible reasons include:
>
>     * There is a typo in the target name.
>     * A find_package call is missing for an IMPORTED target.
>     * An ALIAS target is missing.

See also: https://bugs.gentoo.org/930064

Signed-off-by: Z. Liu <zhixu.liu@gmail.com>

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 51842026837..19dbba5e16d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -384,13 +384,19 @@ if(WITH_BREAKPAD)
     IMPORTED_LINK_INTERFACE_LANGUAGES "CXX")
 endif(WITH_BREAKPAD)
 
+option(WITH_SYSTEM_OPENTELEMETRY "build against system opentelemetry" OFF)
 if(WITH_JAEGER)
   find_package(thrift 0.13.0 REQUIRED)
-  include(BuildOpentelemetry)
-  build_opentelemetry()
   add_library(jaeger_base INTERFACE)
-  target_link_libraries(jaeger_base INTERFACE opentelemetry::libopentelemetry
-    thrift::libthrift)
+  if(WITH_SYSTEM_OPENTELEMETRY)
+    find_package(opentelemetry-cpp REQUIRED)
+    target_link_libraries(jaeger_base INTERFACE ${OPENTELEMETRY_CPP_LIBRARIES})
+  else()
+    include(BuildOpentelemetry)
+    build_opentelemetry()
+    target_link_libraries(jaeger_base INTERFACE opentelemetry::libopentelemetry)
+  endif()
+  target_link_libraries(jaeger_base INTERFACE thrift::libthrift)
 endif()
 
 set(mds_files)
-- 
2.49.1