Fix multiple MKL targets

Author: huydhn

CMakeLists.txt

@@ -750,7 +750,9 @@ if(EXECUTORCH_BUILD_PYBIND)
   endif()
 
   # find pytorch lib, to allow pybind to take at::Tensor as input/output
-  find_package(Torch CONFIG REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch CONFIG REQUIRED)
+  endif()
   find_library(
     TORCH_PYTHON_LIBRARY torch_python PATHS "${TORCH_INSTALL_PREFIX}/lib"
   )

build/Codegen.cmake

@@ -146,7 +146,9 @@ function(gen_custom_ops_aot_lib)
     ${_out_dir}/CustomOpsNativeFunctions.h "${GEN_KERNEL_SOURCES}"
   )
   # Find `Torch`.
-  find_package(Torch REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch REQUIRED)
+  endif()
   # This lib uses ATen lib, so we explicitly enable rtti and exceptions.
   target_compile_options(${GEN_LIB_NAME} PRIVATE -frtti -fexceptions)
   target_compile_definitions(${GEN_LIB_NAME} PRIVATE USE_ATEN_LIB=1)

extension/llm/custom_ops/CMakeLists.txt

@@ -69,7 +69,9 @@ install(TARGETS custom_ops DESTINATION lib)
 
 if(EXECUTORCH_BUILD_KERNELS_CUSTOM_AOT)
   # Add a AOT library
-  find_package(Torch CONFIG REQUIRED)
+  if(NOT TARGET torch)
+    find_package(Torch CONFIG REQUIRED)
+  endif()
   add_library(
     custom_ops_aot_lib SHARED
     ${_custom_ops__srcs}