We were passing a max_output_len that was too small, so every call to
bech32_encode was failing. Now we set max_output_len to the full size of
bech32_str.
I did this by copying the updated bech32 code, and then re-patching in
our minor changes:
1. Headers modded (we need size_t)
2. Explicit length for bech32_encode/decode (not 90).
3. Exposing and bech32_ prefix for convert_bits, charset, charset_rev.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
