message: Fix use of TF Lite as a CMake subproject.
  This also fixes exposure of public include paths when
  depending upon the tensorflow-lite library target.
diff: @@ -39,12 +39,12 @@ set(TENSORFLOW_SOURCE_DIR "" CACHE PATH
  )
  if(NOT TENSORFLOW_SOURCE_DIR)
  get_filename_component(TENSORFLOW_SOURCE_DIR
  - "${CMAKE_SOURCE_DIR}/../../"
  + "${CMAKE_CURRENT_LIST_DIR}/../../"
  ABSOLUTE
  )
  endif()
  set(TF_SOURCE_DIR "${TENSORFLOW_SOURCE_DIR}/tensorflow")
  -set(TFLITE_SOURCE_DIR "${CMAKE_SOURCE_DIR}")
  +set(TFLITE_SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}")
  set(CMAKE_MODULE_PATH
  "${TFLITE_SOURCE_DIR}/tools/cmake/modules"
  ${CMAKE_MODULE_PATH}
  @@ -266,11 +266,14 @@ populate_tflite_source_vars("kernels/internal/reference/sparse_ops"
  )
  # Common include directories
  -include_directories(
  - BEFORE
  +set(TFLITE_INCLUDE_DIRS
  "${TENSORFLOW_SOURCE_DIR}"
  "${TFLITE_FLATBUFFERS_SCHEMA_DIR}"
  )
  +include_directories(
  + BEFORE
  + ${TFLITE_INCLUDE_DIRS}
  +)
  # TFLite library
  add_library(tensorflow-lite
  @@ -295,6 +298,10 @@ add_library(tensorflow-lite
  ${TFLITE_NNAPI_SRCS}
  ${TFLITE_SRCS}
  )
  +target_include_directories(tensorflow-lite
  + PUBLIC
  + ${TFLITE_INCLUDE_DIRS}
  +)
  target_link_libraries(tensorflow-lite
  PUBLIC
  Eigen3::Eigen
  