Okay but that just makes it all more mysterious. Why would you set it to #pragma. Does it affect the program behavior somehow? Also why is -f sent as the name of process to emacs instead of as the first argument?
It was a joke and apparently the person who wrote the code thought that would be funny. execl actually replaces the current running process (the compiler) with the new one, so this very much does not doing anything useful.
I think it doesn't change the behavior at all. I think it means that if you run "ps", it will show up as "#pragma" instead of as "hack" or "rogue".