Yes, the fact that calling conventions *changed* with prototypes in a way that w...

Yes, the fact that calling conventions changed with prototypes in a way that was incompatible with and could not be duplicated by the existing calling conventions was a mistake.

I wrote a little about a very similar case with Objective-C and the default 'id' argument and return type here: http://blog.metaobject.com/2014/03/cargo-cult-typing-or-obje...