inference engine should system pugixml if available

[tripzero]

https://github.com/opencv/dldt/blob/2018/inference-engine/thirdparty/CMakeLists.txt#L10

[shubha-ramani]

Dear tripzero, I don't understand your comment. Can you kindly clarify it ?

Thanks,

Shubha

[alalek]

• buld/install
• feature

Prefer using of system library (for example, installed via apt-get with "-dev" packages) instead of bundled 3rdparty code.

[tripzero]

alalek is correct.

[tripzero]

Any update on this? I had to disable the "add_subdir(pugixml)" line in inference-engine/thirdparty/CMakeLists.txt to avoid getting multiple cmake files that reference/depend on different versions of pugixml. The InferenceEngine-*Debug.cmake referenced 1.0.7 while the system had a newer version installed. The result was I couldn't build opencv with the InferenceEngine backend because pugixml 1.0.7 didn't exist on the system.

find_package is your friend.

[tripzero]

I would argue this is NOT a feature request, but a bug. The result without this change is a broken dldt system (or elsewhere in compute stack) that may compile against or run against a different version than is intended. Without the "hack" I did to fix this, I had runtime errors.

[ilyachur]

We have a PR: #2502

This PR allows to use system pugixml.