Update cmake support of TFLite minimal example

Created a CMakeLists.txt under the lite/examples/minimal

Usage)

$ git clone https://github.com/tensorflow/tensorflow.git tensorflow_src
$ mkdir minimal_build
$ cd miniaml_build
$ cmake ../tensorflow_src/tensorflow/lite/examples/minimal
$ cmake --build . -j

PiperOrigin-RevId: 339977906
Change-Id: I85cada5430407e72354d0a31a17584c48407db2f

tensorflow/lite/CMakeLists.txt

@@ -450,12 +450,3 @@ target_link_libraries(benchmark_model
     ${TFLITE_BENCHMARK_LIBS}
 )
 
-# TFLite minimal example
-add_executable(minimal
-  EXCLUDE_FROM_ALL
-    ${TFLITE_SOURCE_DIR}/examples/minimal/minimal.cc
-)
-target_link_libraries(minimal
-  tensorflow-lite
-  ${CMAKE_DL_LIBS}
-)

tensorflow/lite/examples/minimal/CMakeLists.txt

+#
+# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# Builds the minimal Tensorflow Lite example.
+
+cmake_minimum_required(VERSION 3.16)
+project(minimal C CXX)
+
+set(TENSORFLOW_SOURCE_DIR "" CACHE PATH
+  "Directory that contains the TensorFlow project"
+)
+if(NOT TENSORFLOW_SOURCE_DIR)
+  get_filename_component(TENSORFLOW_SOURCE_DIR
+    "${CMAKE_CURRENT_LIST_DIR}/../../../../"
+    ABSOLUTE
+  )
+endif()
+
+add_subdirectory(
+  "${TENSORFLOW_SOURCE_DIR}/tensorflow/lite"
+  "${CMAKE_CURRENT_BINARY_DIR}/tensorflow-lite"
+  EXCLUDE_FROM_ALL
+)
+
+add_executable(minimal
+  minimal.cc
+)
+target_link_libraries(minimal
+  tensorflow-lite
+  ${CMAKE_DL_LIBS}
+)

tensorflow/lite/examples/minimal/README.md

+# TensorFlow Lite C++ minimal example
+
+This example shows how you can build a simple TensorFlow Lite application.
+
+#### Step 1. Install CMake tool
+
+It requires CMake 3.16 or higher. On Ubuntu, you can simply run the following
+command.
+
+```sh
+sudo apt-get install cmake
+```
+
+Or you can follow
+[the official cmake installation guide](https://cmake.org/install/)
+
+#### Step 2. Clone TensorFlow repository
+
+```sh
+git clone https://github.com/tensorflow/tensorflow.git tensorflow_src
+```
+
+#### Step 3. Create CMake build directory and run CMake tool
+
+```sh
+mkdir minimal_build
+cd minimal_build
+cmake ../tensorflow_src/tensorflow/lite/examples/minimal
+```
+
+#### Step 4. Build TensorFlow Lite
+
+In the minimal_build directory,
+
+```sh
+cmake --build . -j
+```