Normally you would specify it in the project file. Why do you want to specify it in the code?

What you could do if you want to set the executable name at runtime is to check argv[0], then if it's not correct you could copy that file to the filename you want, then launch that new executable, exit, and in the new executable check if this has just happened and delete the old executable.

Anyway there doesn't seem to be anything here that suggests /OUT can be overridden by anything in the source: