pub const STDLIB_FN_BASE: u16 = 40_000;Expand description
the first fn-id reserved for the native standard library.
codegen assigns user functions dense ids 0..N (into Program::chunks)
and stdlib functions ids STDLIB_FN_BASE + i. the VM’s CALL handler
branches on this threshold: a fn-id at or above it routes to the native
stdlib dispatcher; below it looks up a user chunk. all three modules that
use this value (codegen.rs, vm.rs, stdlib.rs) import it from here so
there is exactly one definition to change.