Hi

Environment

• Pythonnet version: 2.3.0
• Python version: 3.6
• Operating System: Ubuntu 16.04 (VM Google Compute)

Details

It has been impossible to install pythonnet with pip install pythonnet or python setup.py install without adding /p:TargetFrameworkVersion="v4.5" to the setup.py.
Without this line I have :

CSC: error CS0518: The predefined type System.ValueType' is not defined or imported CSC: error CS0518: The predefined type System.Attribute' is not defined or imported
CSC: error CS0518: The predefined type System.Int32' is not defined or imported CSC: error CS0518: The predefined type System.UInt32' is not defined or imported
CSC: error CS0518: The predefined type System.Int64' is not defined or imported CSC: error CS0518: The predefined type System.UInt64' is not defined or imported
CSC: error CS0518: The predefined type System.Single' is not defined or imported CSC: error CS0518: The predefined type System.Double' is not defined or imported
CSC: error CS0518: The predefined type System.Char' is not defined or imported CSC: error CS0518: The predefined type System.Int16' is not defined or imported
CSC: error CS0518: The predefined type System.Decimal' is not defined or imported CSC: error CS0518: The predefined type System.Boolean' is not defined or imported
CSC: error CS0518: The predefined type System.SByte' is not defined or imported CSC: error CS0518: The predefined type System.Byte' is not defined or imported
CSC: error CS0518: The predefined type System.UInt16' is not defined or imported CSC: error CS0518: The predefined type System.String' is not defined or imported
CSC: error CS0518: The predefined type System.Enum' is not defined or imported CSC: error CS0518: The predefined type System.Delegate' is not defined or imported
CSC: error CS0518: The predefined type System.MulticastDelegate' is not defined or imported CSC: error CS0518: The predefined type System.Void' is not defined or imported
CSC: error CS0518: The predefined type System.Array' is not defined or imported CSC: error CS0518: The predefined type System.Type' is not defined or imported
CSC: error CS0518: The predefined type System.Collections.IEnumerator' is not defined or imported CSC: error CS0518: The predefined type System.Collections.IEnumerable' is not defined or imported
CSC: error CS0518: The predefined type System.IDisposable' is not defined or imported CSC: error CS0518: The predefined type System.IntPtr' is not defined or imported
CSC: error CS0518: The predefined type System.UIntPtr' is not defined or imported CSC: error CS0518: The predefined type System.RuntimeFieldHandle' is not defined or imported
CSC: error CS0518: The predefined type System.RuntimeTypeHandle' is not defined or imported CSC: error CS0518: The predefined type System.Exception' is not defined or imported

Is that a normal behavior ?

Cheers