Android demo: Docker improvements (#3499)

- Install OpenCL headers
- Set ANDROID_HOME environment variable

docker/Dockerfile.demo_android

@@ -52,6 +52,8 @@ ENV PATH ${PATH}:${VULKAN_SDK}/bin
 ENV LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:${VULKAN_SDK}/lib
 ENV VK_LAYER_PATH ${VULKAN_SDK}/etc/explicit_layer.d
 
+RUN git clone https://github.com/KhronosGroup/OpenCL-Headers /usr/local/OpenCL-Headers/
+
 # Build TVM
 RUN cd /usr && \
     git clone --depth=1 https://github.com/dmlc/tvm --recursive && \
@@ -69,3 +71,4 @@ RUN cd /usr && \
 
 # Environment variables
 ENV PYTHONPATH=/usr/tvm/python:/usr/tvm/topi/python:/usr/tvm/nnvm/python/:/usr/tvm/vta/python:${PYTHONPATH}
+ENV ANDROID_HOME=/opt/android-sdk-linux/

tutorials/frontend/deploy_model_on_android.py

@@ -130,8 +130,8 @@ from tvm.contrib.download import download_testdata
 #
 #   # the additional include headers you want to add, e.g., SDK_PATH/adrenosdk/Development/Inc
 #   ADD_C_INCLUDES += /work/adrenosdk-linux-5_0/Development/Inc
-#   # download from https://github.com/KhronosGroup/OpenCL-Headers
-#   ADD_C_INCLUDES += /workspace/3rdparty/OpenCL-Headers/
+#   # downloaded from https://github.com/KhronosGroup/OpenCL-Headers
+#   ADD_C_INCLUDES += /usr/local/OpenCL-Headers/
 #
 #   # the additional link libs you want to add, e.g., ANDROID_LIB_PATH/libOpenCL.so
 #   ADD_LDLIBS = /workspace/pull-from-android-device/libOpenCL.so