Upgrade Rust to 1.78.0

[Zixing Liu]

Upgrade Rust to 1.78.0

Notable changes in 1.78:

* Diagnostic attributes: you can now customize warning or error messages in your library to let the user of your library better understand their situation.
* Asserting unsafe preconditions: Standard library built in the release mode now also has the bound and alignment checks.

https://blog.rust-lang.org/2024/05/02/Rust-1.78.0.html

[Zixing Liu (liushuyu-011)]

Preliminary packages have been uploaded to https://launchpad.net/~liushuyu-011/+archive/ubuntu/rust-updates-1.78/+packages.
The complete corresponding source can be found at https://git.launchpad.net/~canonical-foundations/ubuntu/+source/rustc/tree/?h=merge-1.78.

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Lintian report:
Now running lintian rustc-1.78_1.78.0+dfsg1ubuntu1-0ubuntu0.30_source.changes ...
E: rustc-1.78 source: field-too-long Vendored-Sources-Rust (11614 chars > 5000)
E: rustc-1.78 source: unknown-file-in-debian-source [debian/source/lintian-overrides.in]
E: rustc-1.78 source: version-substvar-for-external-package Depends ${binary:Version} cargo-1.78 -> rustc [debian/control:305]
W: rustc-1.78 source: mismatched-override missing-license-paragraph-in-dep5-copyright debian/copyright mpl-2.0+ (*) [debian/source/lintian-overrides:16]
W: rustc-1.78 source: unknown-field Vendored-Sources-Rust
N: 0 hints overridden; 1 unused override
N: Some overrides were ignored.
N: Use --verbose for more information.
Finished running lintian.
Now signing changes and any dsc files...
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Autopkgtest reports:

https://autopkgtest.ubuntu.com/results/autopkgtest-oracular-liushuyu-011-rust-updates-1.78/?format=plain