Failed at compiling

Greetings,

I am not used to Xcode so I totally don’t understand how to solve a problem.
the error I get when compiling is:

file not found: /usr/lib/libstdc++.6.dylib for architecture x86_64

when I search myself I can find the file under the exact same path on my mac.
Can anyone tell me what this error is and how to solve it?
I used xcode 11.7 and the beta6 12.0.