net-p2p/c-lightning: fix on head and wait bitcoind
- Fix compilation on FreeBSD 13-CURRENT
- Instruct rc(8) to start lightningd after bitcoind, if the latter is to be started on this host.
- Wait for bitcoind RPC to be available before starting lightningd because:
- even though bitcoind would start and its rc script exit, it will not serve RPC requests immediately
- lightningd would not start if bitcoind RPC is not available