Declares the function imported from DLL as thread-safe.
It will increase the performance of calculation and optimization of the studies that use external DLLs.
It is not recommended to apply ThreadSafe attribute to the functions exported from elkit32.dll (for example FindAddress_).
DEFINEDLLFUNC: ThreadSafe, "user32.dll", Void, "MessageBeep", Int;
Will declare MessageBeep function of user32.dll as thread-safe.