Disable Haiku in CI due to upstream breakage, and fix a no_std error.

Author: sunfishcode

.github/workflows/main.yml

@@ -217,7 +217,8 @@ jobs:
     # Omit --all-targets on gnu_ilp32 because dev-dependency tempfile depends on an older rustix
     - run: cargo check -Z build-std --target aarch64-unknown-linux-gnu_ilp32 --features=all-apis
     # Omit --all-targets on haiku because not all the tests build yet.
-    - run: cargo check -Z build-std --target x86_64-unknown-haiku --features=all-apis
+    # Temporarily disable this because the target appears to have breakage on nightly.
+    #- run: cargo check -Z build-std --target x86_64-unknown-haiku --features=all-apis
     - run: cargo check -Z build-std --target x86_64-uwp-windows-msvc --all-targets --features=all-apis
     # Temporarily disable riscv32imc-esp-espidf due to std using SOMAXCONN.
     #- run: cargo check -Z build-std --target=riscv32imc-esp-espidf --features=all-apis

src/net/netdevice.rs

@@ -18,7 +18,7 @@
 //! [Linux]: https://man7.org/linux/man-pages/man7/netdevice.7.html
 
 #[cfg(feature = "alloc")]
-use crate::alloc::string::String;
+use alloc::string::String;
 use crate::fd::AsFd;
 use crate::io;