hyper: drop support

lib : remove all hyper code
configure: stop detecting hyper
docs: no more mention of hyper
tests: mo more special-handling of hyper builds
CI: no jobs using hyper

Closes #15120

docs/internals/HYPER.md

@@ -1,78 +0,0 @@
-<!--
-Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
-
-SPDX-License-Identifier: curl
--->
-
-# Hyper
-
-Hyper is a separate HTTP library written in Rust. curl can be told to use this
-library as a backend to deal with HTTP.
-
-## EXPERIMENTAL
-
-Hyper support in curl is considered **EXPERIMENTAL** until further notice. It
-needs to be explicitly enabled at build-time.
-
-Further development and tweaking of the Hyper backend support in curl happens
-in the master branch using pull-requests, just like ordinary changes.
-
-## Hyper version
-
-The C API for Hyper is brand new and is still under development.
-
-## Build curl with hyper
-
-Using Rust 1.64.0 or later, build hyper and enable its C API like this:
-
-     % git clone https://github.com/hyperium/hyper
-     % cd hyper
-     % RUSTFLAGS="--cfg hyper_unstable_ffi" cargo rustc --features client,http1,http2,ffi --crate-type cdylib
-
-Also, `--release` can be added for a release (optimized) build.
-
-Build curl to use hyper's C API:
-
-     % git clone https://github.com/curl/curl
-     % cd curl
-     % autoreconf -fi
-     % ./configure LDFLAGS="-Wl,-rpath,<hyper-dir>/target/debug -Wl,-rpath,<hyper-dir>/target/release" --with-openssl --with-hyper=<hyper-dir>
-     % make
-
-# Using Hyper internally
-
-Hyper is a low level HTTP transport library. curl itself provides all HTTP
-headers and Hyper provides all received headers back to curl.
-
-Therefore, most of the "header logic" in curl as in responding to and acting
-on specific input and output headers are done the same way in curl code.
-
-The API in Hyper delivers received HTTP headers as (cleaned up) name=value
-pairs, making it impossible for curl to know the exact byte representation
-over the wire with Hyper.
-
-## Limitations
-
-The hyper backend does not support
-
-- `CURLOPT_IGNORE_CONTENT_LENGTH`
-- `--raw` and disabling `CURLOPT_HTTP_TRANSFER_DECODING`
-- RTSP
-- hyper is much stricter about what HTTP header contents it allows
-- leading whitespace in first HTTP/1 response header
-- HTTP/0.9
-- HTTP/2 upgrade using HTTP:// URLs. Aka 'h2c'
-- HTTP/2 in general. Hyper has support for HTTP/2 but the curl side
-  needs changes so that a `hyper_clientconn` can last for the duration
-  of a connection. Probably this means turning the Hyper HTTP/2 backend
-  into a connection filter.
-
-## Remaining issues
-
-This backend is still not feature complete with the native backend. Areas that
-still need attention and verification include:
-
-- multiplexed HTTP/2
-- h2 Upgrade:
-- receiving HTTP/1 trailers
-- sending HTTP/1 trailers

docs/internals/WEBSOCKET.md

@@ -99,7 +99,6 @@ Ideas:
 
 - Verify the Sec-WebSocket-Accept response. It requires a sha-1 function.
 - Verify Sec-WebSocket-Extensions and Sec-WebSocket-Protocol in the response
-- Make WebSocket work with hyper
 - Consider a `curl_ws_poll()`
 - Make sure WebSocket code paths are fuzzed
 - Add client-side PING interval