Add runtime error UnsafeMultithreaded, for use when a program with multiple threads calls a function that is unsafe in a multithreaded environment.
Add runtime error UnsafeMultithreaded, for use when a program with multiple
threads calls a function that is unsafe in a multithreaded environment.

mheinsen/seec,seec-team/seec,seec-team/seec,seec-team/seec,seec-team/seec,mheinsen/seec,mheinsen/seec,mheinsen/seec,seec-team/seec,mheinsen/seec