Another point why i'd prefer to use a single struct (call it foo, or
anything else) for interpreter globals, is to encapsulate all global
values in single place:
- VM variables
- pointers to VM functions.

And in generated code use foo->bar for values, and foo->bar(...) for
function calls.

This will give me ability to replace a function pointer with own code
on the fly in running VM, without recompiling code at all.
And moreover, this eliminates the need in having InterpreterProxy
variable for each plugin.