And turn "" includes into full-path (which makes it easier to put
config.h first, and finds some cases check-includes.sh missed
previously).
config.h sets _GNU_SOURCE which really needs to be done before any
'#includes': we mainly got away with it with glibc, but other platforms
like Alpine may have stricter requirements.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
WebSocket is a bit weird:
1. It starts like an HTTP connection, but they send special headers.
2. We reply with special headers, one of which involves SHA1 of one of theirs.
3. We are then in WebSocket mode, where each frame starts with a 2-20 byte
header.
We relay data in a simplistic way: if either side sends something, we
read it and relay it synchronously. That avoids any gratuitous
buffering.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>