Allow for crosscompilation of flatbuffer for NPU plugin

Author: jwludzik

thirdparty/dependencies.cmake

@@ -449,12 +449,16 @@ if(ENABLE_OV_TF_LITE_FRONTEND OR ENABLE_INTEL_NPU)
         add_subdirectory(thirdparty/flatbuffers EXCLUDE_FROM_ALL)
         if(ENABLE_INTEL_NPU)
             # NPU plugin requires flatbuffers to be built always
-            add_custom_target(npu_compiler_flatbuffers ALL DEPENDS flatbuffers flatc)
+            add_custom_target(npu_compiler_flatbuffers ALL DEPENDS flatbuffers ${flatbuffers_DEPENDENCY})
             set(flatbuffers_root "${CMAKE_CURRENT_SOURCE_DIR}/thirdparty/flatbuffers/flatbuffers")
             ov_developer_package_export_targets(TARGET flatbuffers
                     INSTALL_INCLUDE_DIRECTORIES "${flatbuffers_root}/include/")
             ov_developer_package_export_targets(TARGET ProjectConfig)
-            install(TARGETS flatc DESTINATION "developer_package/bin" COMPONENT developer_package EXCLUDE_FROM_ALL)
+            install(FILES ${flatbuffers_COMPILER} DESTINATION "developer_package/bin" COMPONENT developer_package EXCLUDE_FROM_ALL)
+            if (CMAKE_CROSSCOMPILING)
+                # NPU compiler requires flatbuffers and flatc defined as target
+                add_executable(flatc ALIAS flatbuffers::flatc)
+            endif()
         endif()
     endif()