Openingd can query them itself (as dualopend already does).  And move
the two feature args next to each other on the wire.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We want to use this to handle the simple description for channel_type.

It also needs to handle variable-size types (just like subtypes).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

We make it a first-class citizen internally, even though we won't use
it over the wire (at least, non-experimental builds).  This scheme
follows the latest draft, in which features are flagged compulsory.

We also add several helper functions.

Since uses the *even* bits (as per latest spec), not the *odd* bits,
we have some other fixups.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

… bools.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Instead of explicit option_static_remotekey and option_anchor_outputs flags.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Currently we actually insist it's the default, but in future it could be
different.

We also need to tell openingd what the channel_type was, if we resume
via openingd_funder_complete().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

It was merged (but this doesn't update the BOLT quotes, that's in another patch).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: Protocol: We now send and support channel_type in channel open (not dual-funding though).

e.g. you can negotiate anchor_outputs, but still ask for a
non-anchor-output channel.

If/when we make those features compulsory, downgrade will
not be allowed.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

It's not a separate option, but lnprototest needs it to know to expect
the tlvs.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

This was just a minor leak, found by CI for
test_openchannel_hook_chaining.  We didn't call negotiation_aborted
which frees various fields: negotiation_failed() does that for us.

```
 MEMLEAK: 0x55b0f2d5f3c8
   label=common/channel_type.c:19:struct channel_type
   backtrace:
     ccan/ccan/tal/tal.c:442 (tal_alloc_)
     common/channel_type.c:19 (channel_type_none)
     common/channel_type.c:27 (channel_type_static_remotekey)
     common/channel_type.c:136 (channel_type_accept)
     openingd/openingd.c:844 (fundee_channel)
     openingd/openingd.c:1240 (handle_peer_in)
     openingd/openingd.c:1510 (main)
   parents:
     openingd/openingd.c:1414:struct state
```

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>