XCode Apple Mach-O Linker Error

I had to install Unity after a while because App Store asked me to update my game to support iOS x64. I managed to recompile the game using Unity 5. It runs fine but I soon discovered that the main plugin I was using is not working fine anymore because of the new physics. So I built it again using Unity 4.7

Export was fine, but compiling with XCode (latest version 8) is giving some errors.

I already tried changing simulator (I have no physical device), cleaning and rebuilding project, restarting system…

You need to change the SDK version on player settings to simulator