Hi Marc,
Gambit's compiler is deterministic right?
(As in Scheme to GVM, GVM to C or binary. Underlying C compiler's determinism is a separate matter altogether.)
A consideration could be that compilation output is a function of |gensym| and therefore its counter must be managed for deterministic compilation.
Another consideration that if running more instances of the compiler in one Gambit process concurrently, the |gensym| calls could have arbitrary order and therefore determinism break.
Adam