changes for vxworks

[Anupamvashistha2002]

Summary

This PR improves support for the vxworks target in the Rust standard library by fixing platform-specific issues and ensuring better compatibility with VxWorks.

These changes are isolated to vxworks and do not affect other platforms.

Notes

Tested manually on a VxWorks environment. Feedback on potential edge cases or additional tests would be appreciated.

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[rust-log-analyzer]

The job tidy failed! Check out the build log: (web) (plain enhanced) (plain)

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##[endgroup]
[TIMING:end] tool::ToolBuild { build_compiler: Compiler { stage: 0, host: x86_64-unknown-linux-gnu, forced_compiler: false }, target: x86_64-unknown-linux-gnu, tool: "tidy", path: "src/tools/tidy", mode: ToolBootstrap, source_type: InTree, extra_features: [], allow_features: "", cargo_args: [], artifact_kind: Binary } -- 11.121
[TIMING:end] tool::Tidy { compiler: Compiler { stage: 0, host: x86_64-unknown-linux-gnu, forced_compiler: false }, target: x86_64-unknown-linux-gnu } -- 0.000
fmt check
Diff in /checkout/library/std/src/fs/tests.rs:802:
     let canary = tmpdir.join("do_not_delete");
     check!(check!(File::create(&canary)).write(b"foo"));
     let result = fs::remove_dir_all(&canary);
-    #[cfg(all(not(target_os = "vxworks"),unix))]
+    #[cfg(all(not(target_os = "vxworks"), unix))]
     error!(result, "Not a directory");
     #[cfg(target_os = "vxworks")]
     error!(result, "not a directory");
fmt: checked 6344 files
Bootstrap failed while executing `test src/tools/tidy tidyselftest --extra-checks=py,cpp,js,spellcheck`
Build completed unsuccessfully in 0:00:48
  local time: Mon Sep  1 05:22:38 UTC 2025
  network time: Mon, 01 Sep 2025 05:22:38 GMT