Please allow to use the external onnx

[yurivict]

I have onnx as a package on FreeBSD, and would like to just use it instead of bundling it.

Could you please create the cmake option that would allow to use external onnx?

[okdshin]

Sorry for my late reply.　Current menoh supports only 1.4.1 .
I think FreeBSD package's onnx is not 1.4.1 . So please build.
Or, As I told on #226, you can use chainer-compiler's menoh API. Although maybe you need to build onnx package as well, it supports latest onnx.