There's a comment in pass1.c that C doesn't allow initialisation of an entire struct to 0
in the way that Imp does, and the code handles that with memset.

In fact C *does* support zeroing an entire struct (maybe this is just in later standards?)
which you can do by: MyStruct s = {0}; // All members initialized to 0/NULL

This is even *supposed to* set pointer values to NULL correctly even if NULL isn't
represented as 0 on the target machine.

Actully this sounds vaguely famiiar, maybe I've noticed this previously and
already added it to imptoc?  I need to check, when I get that project going again.

(GT, 20260126)