quiche build instructions need update after the quiche release avalanche

[av223119]

Specify which documentation you found a problem with

https://github.com/curl/curl/blob/master/docs/HTTP3.md#quiche-version

The problem

Documentation specifies that the quiche build is experimental, nevertheless the given instructions worked fine until the yesterday avalanche of quiche releases; 24 hours ago curl could be built against the latest quiche release available (0.24.5) according to the instructions provided. Now, however, quiche version has been bumped to 0.29.2 and the instructions don't work anymore. Notably, there's no quiche/deps/boringssl anymore; instead one should find a directory 'boringssl/src' in target/release/build and adjust paths accordingly:

BORINGSSL=$(find $PWD -wholename '*/boringssl/src' -type d)
mkdir $BORINGSSL/lib
ln -vnf $(find target/release -name libcrypto.a -o -name libssl.a) $BORINGSSL/lib/

and adjust --with-openssl accordingly

[vszakats]

Are you up opening a pull request?

The change came with quiche 0.29.0, which replaced vendoring
BoringSSL with pulling it as a package. This made the BoringSSL
directory contain a hash a no longer stable. Ref updating build
steps in curl CI:
252b82f #21730

[icing]

Can you check if the description in #22109 works for you? Thanks.

[av223119]

The instruction does work indeed.

[av223119]

@vszakats Sorry, I probably should have created a PR in the first place after I modified my build script. But @icing 's solution works perfectly fine.