ctest: test ctest-next in ctest-test

[mbyx]

Description

• Adds support for testing ctest-next using the same test crate as ctest.
• Additionally fixes some bugs in the template (unnecessary unsafe, and missing c_char import).
• Removes tests for &str, they can be added back in with separate constants that are skipped by ctest-next if needed.
• Adds link_name support for functions and statics, which goes unused right now but will be used when tests for functions and statics are implemented.
• Removes the dependency on libc, as ctest-next cannot resolve it (can be fixed later, although it isn't really necessary anywhere)

Sources

Checklist

• Relevant tests in libc-test/semver have been updated
• No placeholder or unstable values like *LAST or *MAX are
  included (see #3131)
• Tested locally (cd libc-test && cargo test --target mytarget);
  especially relevant for platforms that may not be checked in CI

[mbyx]

Unfortunately, I have no idea what the errors mean.

[tgross35]

Unfortunately, I have no idea what the errors mean.

Can you try updating the templates to change extern "C" { ... } to unsafe extern "C" { ... }? that's a recent edition change

[mbyx]

Fixes the previous error, but a new one pops up, looks like it's a mix of forgetting to ignore 2024 edition crates for targets that don't support it, and the fact that the old ctest cannot parse new syntax.

If we want to keep both we'll probably have to keep them separate as they were before. The edition was changed to 2024 since ctest-next is a dependency.