Include custom ops in xnn_executor_runner if they're built (#9069)

(We should probably merge xnn_executor_runner and executor_runner if there's no particular use for a portable-only runner, but hey this is an incremental improvement.)

Author: swolchok

backends/xnnpack/CMakeLists.txt

@@ -10,7 +10,7 @@
 # cmake-format -i CMakeLists.txt
 # ~~~
 
-cmake_minimum_required(VERSION 3.19)
+cmake_minimum_required(VERSION 3.24)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
@@ -124,6 +124,10 @@ else()
   list(APPEND xnn_executor_runner_libs portable_ops_lib)
 endif()
 
+if(EXECUTORCH_BUILD_KERNELS_CUSTOM)
+  list(APPEND xnn_executor_runner_libs $<LINK_LIBRARY:WHOLE_ARCHIVE,custom_ops>)
+endif()
+
 list(APPEND xnn_executor_runner_libs xnnpack_backend executorch)
 
 # ios can only build library but not binary