Trivia question: when you run a random configure scripts, how many processes does it spawn?
Before reading further, try to think of the answer by yourself. Just do it. Pick a number you think is the correct answer.
Measuring this is simple. You can do it with the following command:
strace -c -f -e trace=fork,vfork,clone,execve bash -c ./configure
Different configure scripts have different results, of course. I ran this on the configure script of RPM, which I happened to have handy.
And the correct answer is ...
Aren't you glad that processes are cheap?