Hi Shai,
thanks for your response. I've narrowed down the root of the problem. As you said, it was located in the BasicosBll class, specifically in a long method which I use to load up some extensive data to avoid using a web service for it. I provide the said method on the attached text file for your revision. After commenting out all the values the build worked perfectly, please note that this piece of code has been since the beginning of the app's development and has worked just fine until the change to xcode 9.2.
I hope this helps in finding a solution to this problem, thanks for your collaboration.
Cheers,