That's how I read it too. The existing C code which is not passing the expected parameter was a result of "hey I've tried it without and it worked" approach. It

That's how I read it too. The existing C code which is not passing the expected parameter was a result of "hey I've tried it without and it worked" approach. It "worked" at the moment, and only for that specific compiler, but once the compiler started to rely on the "fact" that the parameter is "by definition there" some the previously "working" programs started to break. And this outcome is in fact nothing special to C and Fortran. I can just as well write a shell script (or any other) which "expects" that there is a parameter and if I don't use it and I later start to depend on it I'm sure there will be some other scripts calling that one and passing something else than what was "defined" as expected to be passed. On that topic, erverybody should read ryl00's comment here. Having more than one really different target is the only practically effective path to immunize from these kinds of dependencies. For me, it's one of good arguments against the "monoculture" software targets.