lib/src: white space edits to comply better with code style

... as checksrc now finds and complains about these.

Closes #14921

lib: use FMT_ as prefix instead of CURL_FORMAT_

For printf format defines used internally. Makes the code slighly
easier to read.

Closes #14764

lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will

lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers
are not yet fully flushed.

Closes #14220

show more ...

Revert "lib: send eos flag"

This reverts commit be93299f10ef0b2bf7fe5c82140120073831867a.

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers are
not yet fully flushed.

Closes #14220

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code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname

code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname
- file name => filename
- user name = username
- man page => manpage
- run-time => runtime
- set-up => setup
- back-end => backend
- a HTTP => an HTTP
- Two spaces after a period => one space after period

Closes #14073

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http: remove "struct HTTP"

It is not actually used anymore and only contained a dummy struct field.
Remove all traces and uses of it.

Closes #13927

connection: shutdown TLS (for FTP) better

This adds connection shutdown infrastructure and first use for FTP. FTP
data connections, when not encountering an error, are now shut down in a

connection: shutdown TLS (for FTP) better

This adds connection shutdown infrastructure and first use for FTP. FTP
data connections, when not encountering an error, are now shut down in a
blocking way with a 2sec timeout.

- add cfilter `Curl_cft_shutdown` callback
- keep a shutdown start timestamp and timeout at connectdata
- provide shutdown timeout default and member in
`data->set.shutdowntimeout`.
- provide methods for starting, interrogating and clearing
shutdown timers
- provide `Curl_conn_shutdown_blocking()` to shutdown the
`sockindex` filter chain in a blocking way. Use that in FTP.
- add `Curl_conn_cf_poll()` to wait for socket events during
shutdown of a connection filter chain.
This gets the monitoring sockets and events via the filters
"adjust_pollset()" methods. This gives correct behaviour when
shutting down a TLS connection through a HTTP/2 proxy.
- Implement shutdown for all socket filters
- for HTTP/2 and h2 proxying to send GOAWAY
- for TLS backends to the best of their capabilities
- for tcp socket filter to make a final, nonblocking
receive to avoid unwanted RST states
- add shutdown forwarding to happy eyeballers and
https connect ballers when applicable.

Closes #13904

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lib/cf-h1-proxy: silence compiler warnings (gcc 14)

They came up ealier with gcc 12 (Windows), but apparently gcc 14 is
still reporting them, also under Linux.

```
/home/run

lib/cf-h1-proxy: silence compiler warnings (gcc 14)

They came up ealier with gcc 12 (Windows), but apparently gcc 14 is
still reporting them, also under Linux.

```
/home/runner/work/curl-for-win/curl-for-win/curl/lib/cf-h1-proxy.c: In function 'cf_h1_proxy_close':
/home/runner/work/curl-for-win/curl-for-win/curl/lib/cf-h1-proxy.c:1060:17: warning: null pointer dereference [-Wnull-dereference]
1060 | cf->connected = FALSE;
/home/runner/work/curl-for-win/curl-for-win/curl/lib/cf-h1-proxy.c:1061:8: warning: null pointer dereference [-Wnull-dereference]
1061 | if(cf->ctx) {
| ~~^~~~~
In function 'tunnel_free',
inlined from 'cf_h1_proxy_destroy' at /home/runner/work/curl-for-win/curl-for-win/curl/lib/cf-h1-proxy.c:1053:3:
/home/runner/work/curl-for-win/curl-for-win/curl/lib/cf-h1-proxy.c:198:27: warning: null pointer dereference [-Wnull-dereference]
198 | struct h1_tunnel_state *ts = cf->ctx;
| ^~
```
Ref: https://github.com/curl/curl-for-win/actions/runs/8985369476/job/24679219528#step:3:6320

Fixes #13237
Closes #13555

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tls: use shared init code for TCP+QUIC

Closes #13172

http: revisit http_perhapsrewind()

- use facilities provided by client readers better
- work also for non-uploading requests like GET/HEAD
- update documentation

Closes #131

http: revisit http_perhapsrewind()

- use facilities provided by client readers better
- work also for non-uploading requests like GET/HEAD
- update documentation

Closes #13117

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lib: move 'done' parameter to SingleRequests

A transfer may do several `SingleRequest`s for its success. This happens
regularly for authentication, follows and retries on failed connecti

lib: move 'done' parameter to SingleRequests

A transfer may do several `SingleRequest`s for its success. This happens
regularly for authentication, follows and retries on failed connections.
The "readwrite()" calls and functions connected to those carried a `bool
*done` parameter to indicate that the current `SingleRequest` is over.
This may happen before `upload_done` or `download_done` bits of
`SingleRequest` are set.

The problem with that is now `write_resp()` protocol handlers are
invoked in places where the `bool *done` cannot be passed up to the
caller. Instead of being a bool in the call chain, it needs to become a
member of `SingleRequest`, reflecting its state.

This removes the `bool *done` parameter and adds the `done` bit to
`SingleRequest` instead. It adds `Curl_req_soft_reset()` for using a
`SingleRequest` in a follow up, clearing `done` and other
flags/counters.

Closes #13096

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lib: further send/upload handling polish

- Move all the "upload_done" handling to request.c

- add possibility to abort sending of a request
- add `Curl_req_done_sending()` f

lib: further send/upload handling polish

- Move all the "upload_done" handling to request.c

- add possibility to abort sending of a request
- add `Curl_req_done_sending()` for checks
- transfer.c: readwrite_upload() now clean

- removing data->state.ulbuf and data->req.upload_fromhere

- as well as data->req.upload_present
- set data->req.upload_done on having read all from
the client and completely flushed the send buffer

- tftp, remove setting of data->req.upload_fromhere

- serves no purpose as `upload_present` is not set
and the data itself is directly `sendto()` anyway

- smtp, make upload EOB conversion a client reader
- xfer_ulbuf addition

- add xfer_ulbuf for borrowing, similar to xfer_buf
- use in file upload
- use in c-hyper body sending

- h1-proxy, remove init of data->state.uilbuf that is never used
- smb, add own send_buf instead of using data->state.ulbuf

Closes #13010

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lib: Curl_read/Curl_write clarifications

- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to
clarify when and at what level they operate
- send/recv of transfer related

lib: Curl_read/Curl_write clarifications

- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to
clarify when and at what level they operate
- send/recv of transfer related data is now done via
`Curl_xfer_send()/Curl_xfer_recv()` which no longer has
socket/socketindex as parameter. It decides on the transfer
setup of `conn->sockfd` and `conn->writesockfd` on which
connection filter chain to operate.
- send/recv on a specific connection filter chain is done via
`Curl_conn_send()/Curl_conn_recv()` which get the socket index
as parameter.
- rename `Curl_setup_transfer()` to `Curl_xfer_setup()` for
naming consistency
- clarify that the special CURLE_AGAIN hangling to return
`CURLE_OK` with length 0 only applies to `Curl_xfer_send()`
and CURLE_AGAIN is returned by all other send() variants.
- fix a bug in websocket `curl_ws_recv()` that mixed up data
when it arrived in more than a single chunk (to be made
into a sperate PR, also)

Added as documented [in
CLIENT-READER.md](https://github.com/curl/curl/blob/5b1f31dfbab8aef467c419c68aa06dc738cb75d4/docs/CLIENT-READERS.md).

- old `Curl_buffer_send()` completely replaced by new `Curl_req_send()`
- old `Curl_fillreadbuffer()` replaced with `Curl_client_read()`
- HTTP chunked uploads are now formatted in a client reader added when
needed.
- FTP line-end conversions are done in a client reader added when
needed.
- when sending requests headers, remaining buffer space is filled with
body data for sending in "one go". This is independent of the request
body size. Resolves #12938 as now small and large requests have the
same code path.

Changes done to test cases:

- test513: now fails before sending request headers as this initial
"client read" triggers the setup fault. Behaves now the same as in
hyper build
- test547, test555, test1620: fix the length check in the lib code to
only fail for reads *smaller* than expected. This was a bug in the
test code that never triggered in the old implementation.

Closes #12969

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lib: Curl_read/Curl_write clarifications

- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to
clarify when and at what level they operate
- send/recv of transfer related

lib: Curl_read/Curl_write clarifications

- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to
clarify when and at what level they operate
- send/recv of transfer related data is now done via
`Curl_xfer_send()/Curl_xfer_recv()` which no longer has
socket/socketindex as parameter. It decides on the transfer
setup of `conn->sockfd` and `conn->writesockfd` on which
connection filter chain to operate.
- send/recv on a specific connection filter chain is done via
`Curl_conn_send()/Curl_conn_recv()` which get the socket index
as parameter.
- rename `Curl_setup_transfer()` to `Curl_xfer_setup()` for
naming consistency
- clarify that the special CURLE_AGAIN hangling to return
`CURLE_OK` with length 0 only applies to `Curl_xfer_send()`
and CURLE_AGAIN is returned by all other send() variants.
- fix a bug in websocket `curl_ws_recv()` that mixed up data
when it arrived in more than a single chunk

The method for sending not just raw bytes, but bytes that are either
"headers" or "body". The send abstraction stack, to to bottom, now is:

* `Curl_req_send()`: has parameter to indicate amount of header bytes,
buffers all data.
* `Curl_xfer_send()`: knows on which socket index to send, returns
amount of bytes sent.
* `Curl_conn_send()`: called with socket index, returns amount of bytes
sent.

In addition there is `Curl_req_flush()` for writing out all buffered
bytes.

`Curl_req_send()` is active for requests without body,
`Curl_buffer_send()` still being used for others. This is because the
special quirks need to be addressed in future parts:

* `expect-100` handling
* `Curl_fillreadbuffer()` needs to add directly to the new
`data->req.sendbuf`
* special body handlings, like `chunked` encodings and line end
conversions will be moved into something like a Client Reader.

In functions of the pattern `CURLcode xxx_send(..., ssize_t *written)`,
replace the `ssize_t` with a `size_t`. It makes no sense to allow for negative
values as the returned `CURLcode` already specifies error conditions. This
allows easier handling of lengths without casting.

Closes #12964

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lib: send rework

Curl_read/Curl_write clarifications

- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to 1clarify
when and at what level they operate

- sen

lib: send rework

Curl_read/Curl_write clarifications

- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to 1clarify
when and at what level they operate

- send/recv of transfer related data is now done via
`Curl_xfer_send()/Curl_xfer_recv()` which no longer has
socket/socketindex as parameter. It decides on the transfer setup of
`conn->sockfd` and `conn->writesockfd` on which connection filter
chain to operate.

- send/recv on a specific connection filter chain is done via
`Curl_conn_send()/Curl_conn_recv()` which get the socket index as
parameter.

- rename `Curl_setup_transfer()` to `Curl_xfer_setup()` for naming
consistency

- clarify that the special CURLE_AGAIN handling to return `CURLE_OK`
with length 0 only applies to `Curl_xfer_send()` and CURLE_AGAIN is
returned by all other send() variants.

SingleRequest reshuffling

- move functions into request.[ch]
- differentiate between reset and free
- add Curl_req_done() to perform last actions
- add a send `bufq` to SingleRequest for future use in keeping upload data

Closes #12963

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cf-h1-proxy: no CURLOPT_USERAGENT in CONNECT with hyper

Follow-up to 693cd1679361828a which was incomplete

Ref #12680
Closes #12697

lib: replace readwrite with write_resp

This clarifies the handling of server responses by folding the code for
the complicated protocols into their protocol handlers. This concerns
m

lib: replace readwrite with write_resp

This clarifies the handling of server responses by folding the code for
the complicated protocols into their protocol handlers. This concerns
mainly HTTP and its bastard sibling RTSP.

The terms "read" and "write" are often used without clear context if
they refer to the connect or the client/application side of a
transfer. This PR uses "read/write" for operations on the client side
and "send/receive" for the connection, e.g. server side. If this is
considered useful, we can revisit renaming of further methods in another
PR.

Curl's protocol handler `readwrite()` method been changed:

```diff
- CURLcode (*readwrite)(struct Curl_easy *data, struct connectdata *conn,
- const char *buf, size_t blen,
- size_t *pconsumed, bool *readmore);
+ CURLcode (*write_resp)(struct Curl_easy *data, const char *buf, size_t blen,
+ bool is_eos, bool *done);
```

The name was changed to clarify that this writes reponse data to the
client side. The parameter changes are:

* `conn` removed as it always operates on `data->conn`
* `pconsumed` removed as the method needs to handle all data on success
* `readmore` removed as no longer necessary
* `is_eos` as indicator that this is the last call for the transfer
response (end-of-stream).
* `done` TRUE on return iff the transfer response is to be treated as
finished

This change affects many files only because of updated comments in
handlers that provide no implementation. The real change is that the
HTTP protocol handlers now provide an implementation.

The HTTP protocol handlers `write_resp()` implementation will get passed
**all** raw data of a server response for the transfer. The HTTP/1.x
formatted status and headers, as well as the undecoded response
body. `Curl_http_write_resp_hds()` is used internally to parse the
response headers and pass them on. This method is public as the RTSP
protocol handler also uses it.

HTTP/1.1 "chunked" transport encoding is now part of the general
*content encoding* writer stack, just like other encodings. A new flag
`CLIENTWRITE_EOS` was added for the last client write. This allows
writers to verify that they are in a valid end state. The chunked
decoder will check if it indeed has seen the last chunk.

The general response handling in `transfer.c:466` happens in function
`readwrite_data()`. This mainly operates now like:

```
static CURLcode readwrite_data(data, ...)
{
do {
Curl_xfer_recv_resp(data, buf)
...
Curl_xfer_write_resp(data, buf)
...
} while(interested);
...
}
```

All the response data handling is implemented in
`Curl_xfer_write_resp()`. It calls the protocol handler's `write_resp()`
implementation if available, or does the default behaviour.

All raw response data needs to pass through this function. Which also
means that anyone in possession of such data may call
`Curl_xfer_write_resp()`.

Closes #12480

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build: enable missing OpenSSF-recommended warnings, with fixes

https://best.openssf.org/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.html
as of 2023-11-29 [1]

build: enable missing OpenSSF-recommended warnings, with fixes

https://best.openssf.org/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.html
as of 2023-11-29 [1].

Enable new recommended warnings (except `-Wsign-conversion`):

- enable `-Wformat=2` for clang (in both cmake and autotools).
- add `CURL_PRINTF()` internal attribute and mark functions accepting
printf arguments with it. This is a copy of existing
`CURL_TEMP_PRINTF()` but using `__printf__` to make it compatible
with redefinting the `printf` symbol:
https://gcc.gnu.org/onlinedocs/gcc-3.0.4/gcc_5.html#SEC94
- fix `CURL_PRINTF()` and existing `CURL_TEMP_PRINTF()` for
mingw-w64 and enable it on this platform.
- enable `-Wimplicit-fallthrough`.
- enable `-Wtrampolines`.
- add `-Wsign-conversion` commented with a FIXME.
- cmake: enable `-pedantic-errors` the way we do it with autotools.
Follow-up to d5c0351055d5709da8f3e16c91348092fdb481aa #2747
- lib/curl_trc.h: use `CURL_FORMAT()`, this also fixes it to enable format
checks. Previously it was always disabled due to the internal `printf`
macro.

Fix them:

- fix bug where an `set_ipv6_v6only()` call was missed in builds with
`--disable-verbose` / `CURL_DISABLE_VERBOSE_STRINGS=ON`.
- add internal `FALLTHROUGH()` macro.
- replace obsolete fall-through comments with `FALLTHROUGH()`.
- fix fallthrough markups: Delete redundant ones (showing up as
warnings in most cases). Add missing ones. Fix indentation.
- silence `-Wformat-nonliteral` warnings with llvm/clang.
- fix one `-Wformat-nonliteral` warning.
- fix new `-Wformat` and `-Wformat-security` warnings.
- fix `CURL_FORMAT_SOCKET_T` value for mingw-w64. Also move its
definition to `lib/curl_setup.h` allowing use in `tests/server`.
- lib: fix two wrongly passed string arguments in log outputs.
Co-authored-by: Jay Satiro
- fix new `-Wformat` warnings on mingw-w64.

[1] https://github.com/ossf/wg-best-practices-os-developers/blob/56c0fde3895bfc55c8a973ef49a2572c507b2ae1/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C%2B%2B.md

Closes #12489

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transfer: readwrite improvements

- changed header/chunk/handler->readwrite prototypes to accept `buf`,
`blen` and a `pconsumed` pointer. They now get the buffer to work on
and re

transfer: readwrite improvements

- changed header/chunk/handler->readwrite prototypes to accept `buf`,
`blen` and a `pconsumed` pointer. They now get the buffer to work on
and report back how many bytes they consumed
- eliminated `k->str` in SingleRequest
- improved excess data handling to properly calculate with any body data
left in the headerb buffer
- eliminated `k->badheader` enum to only be a bool

Closes #12283

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lib: client writer, part 2, accounting + logging

This PR has these changes:

Renaming of unencode_* to cwriter, e.g. client writers
- documentation of sendf.h functions
- mov

lib: client writer, part 2, accounting + logging

This PR has these changes:

Renaming of unencode_* to cwriter, e.g. client writers
- documentation of sendf.h functions
- move max decode stack checks back to content_encoding.c
- define writer phase which was used as order before
- introduce phases for monitoring inbetween decode phases
- offering default implementations for init/write/close

Add type paramter to client writer's do_write()
- always pass all writes through the writer stack
- writers who only care about BODY data will pass other writes unchanged

add RAW and PROTOCOL client writers
- RAW used for Curl_debug() logging of CURLINFO_DATA_IN
- PROTOCOL used for updates to data->req.bytecount, max_filesize checks and
Curl_pgrsSetDownloadCounter()
- remove all updates of data->req.bytecount and calls to
Curl_pgrsSetDownloadCounter() and Curl_debug() from other code
- adjust test457 expected output to no longer see the excess write

Closes #12184

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lib: introduce struct easy_poll_set for poll information

Connection filter had a `get_select_socks()` method, inspired by the
various `getsocks` functions involved during the lifetime of

lib: introduce struct easy_poll_set for poll information

Connection filter had a `get_select_socks()` method, inspired by the
various `getsocks` functions involved during the lifetime of a
transfer. These, depending on transfer state (CONNECT/DO/DONE/ etc.),
return sockets to monitor and flag if this shall be done for POLLIN
and/or POLLOUT.

Due to this design, sockets and flags could only be added, not
removed. This led to problems in filters like HTTP/2 where flow control
prohibits the sending of data until the peer increases the flow
window. The general transfer loop wants to write, adds POLLOUT, the
socket is writeable but no data can be written.

This leads to cpu busy loops. To prevent that, HTTP/2 did set the
`SEND_HOLD` flag of such a blocked transfer, so the transfer loop cedes
further attempts. This works if only one such filter is involved. If a
HTTP/2 transfer goes through a HTTP/2 proxy, two filters are
setting/clearing this flag and may step on each other's toes.

Connection filters `get_select_socks()` is replaced by
`adjust_pollset()`. They get passed a `struct easy_pollset` that keeps
up to `MAX_SOCKSPEREASYHANDLE` sockets and their `POLLIN|POLLOUT`
flags. This struct is initialized in `multi_getsock()` by calling the
various `getsocks()` implementations based on transfer state, as before.

After protocol handlers/transfer loop have set the sockets and flags
they want, the `easy_pollset` is *always* passed to the filters. Filters
"higher" in the chain are called first, starting at the first
not-yet-connection one. Each filter may add sockets and/or change
flags. When all flags are removed, the socket itself is removed from the
pollset.

Example:

* transfer wants to send, adds POLLOUT
* http/2 filter has a flow control block, removes POLLOUT and adds
POLLIN (it is waiting on a WINDOW_UPDATE from the server)
* TLS filter is connected and changes nothing
* h2-proxy filter also has a flow control block on its tunnel stream,
removes POLLOUT and adds POLLIN also.
* socket filter is connected and changes nothing
* The resulting pollset is then mixed together with all other transfers
and their pollsets, just as before.

Use of `SEND_HOLD` is no longer necessary in the filters.

All filters are adapted for the changed method. The handling in
`multi.c` has been adjusted, but its state handling the the protocol
handlers' `getsocks` method are untouched.

The most affected filters are http/2, ngtcp2, quiche and h2-proxy. TLS
filters needed to be adjusted for the connecting handshake read/write
handling.

No noticeable difference in performance was detected in local scorecard
runs.

Closes #11833

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http: h1/h2 proxy unification

- use shared code for setting up the CONNECT request
when tunneling, used in HTTP/1.x and HTTP/2 proxying
- eliminate use of Curl_buffer_send() and ot

http: h1/h2 proxy unification

- use shared code for setting up the CONNECT request
when tunneling, used in HTTP/1.x and HTTP/2 proxying
- eliminate use of Curl_buffer_send() and other manipulations
of `data->req` or `data->state.ulbuf`

Closes #11808

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lib: disambiguate Curl_client_write flag semantics

- use CLIENTWRITE_BODY *only* when data is actually body data
- add CLIENTWRITE_INFO for meta data that is *not* a HEADER
- debug a

lib: disambiguate Curl_client_write flag semantics

- use CLIENTWRITE_BODY *only* when data is actually body data
- add CLIENTWRITE_INFO for meta data that is *not* a HEADER
- debug assertions that BODY/INFO/HEADER is not used mixed
- move `data->set.include_header` check into Curl_client_write
so protocol handlers no longer have to care
- add special in FTP for `data->set.include_header` for historic,
backward compatible reasons
- move unpausing of client writes from easy.c to sendf.c, so that
code is in one place and can forward flags correctly

Closes #11885

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hyper: fix ownership problems

Some of these changes come from comparing `Curl_http` and
`start_CONNECT`, which are similar, and adding things to them that are
present in one and miss

hyper: fix ownership problems

Some of these changes come from comparing `Curl_http` and
`start_CONNECT`, which are similar, and adding things to them that are
present in one and missing in another.

The most important changes:
- In `start_CONNECT`, add a missing `hyper_clientconn_free` call on the
happy path.
- In `start_CONNECT`, add a missing `hyper_request_free` on the error
path.
- In `bodysend`, add a missing `hyper_body_free` on an early-exit path.
- In `bodysend`, remove an unnecessary `hyper_body_free` on a different
error path that would cause a double-free.
https://docs.rs/hyper/latest/hyper/ffi/fn.hyper_request_set_body.html
says of `hyper_request_set_body`: "This takes ownership of the
hyper_body *, you must not use it or free it after setting it on the
request." This is true even if `hyper_request_set_body` returns an
error; I confirmed this by looking at the hyper source code.

Other changes are minor but make things slightly nicer.

Closes #11745

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