py/persistentcode: Ensure prelude_offset is always initialised.
@@ -337,7 +337,7 @@ STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader, qstr_window_t *qw) {
byte *ip2;
bytecode_prelude_t prelude = {0};
#if MICROPY_EMIT_MACHINE_CODE
- size_t prelude_offset;
+ size_t prelude_offset = 0;
mp_uint_t type_sig = 0;
size_t n_qstr_link = 0;
#endif
