[ONNX] add onnx schema & meson setting

add onnx schema (proto2 & proto3) and add "enable-onnx-interpreter"
meson setting.

ONNX schema is licensed under the Apache License 2.0

Signed-off-by: Seungbaek Hong <sb92.hong@samsung.com>

meson_options.txt

@@ -13,6 +13,7 @@ option('enable-profile', type: 'boolean', value: false)
 option('enable-trace', type: 'boolean', value: false)
 option('enable-debug', type: 'boolean', value: false)
 option('enable-tflite-interpreter', type: 'boolean', value: true)
+option('enable-onnx-interpreter', type: 'boolean', value: false)
 option('enable-memory-swap', type: 'boolean', value: false)
 option('memory-swap-path', type: 'string', value: '')
 option('test-timeout', type: 'integer', value: 60)

nntrainer/compiler/meson.build

@@ -16,6 +16,16 @@ compiler_headers = [
   'compiler_fwd.h'
 ]
 
+if get_option('enable-onnx-interpreter')
+  protobuf_dep = dependency('protobuf', required: true)
+  nntrainer_base_deps += protobuf_dep
+
+  compiler_sources += [
+    'onnx.pb2.cc',
+    'onnx.pb3.cc'
+  ]
+endif
+
 if get_option('enable-tflite-interpreter')
   if not tflite_dep.found()
     error('Tensorflow2-Lite dependency not found')