Rollup merge of rust-lang#126212 - SteveLauC:fix/haiku, r=joboet

fix: build on haiku ## What does this PR do The std is broken on haiku, this PR fixes it. ## To reproduce the issue ```sh $ cargo +nightly --version cargo 1.81.0-nightly (b1feb75d0 2024-06-07) $ cargo new hello $ cd hello $ cargo +nightly check -Zbuild-std --target x86_64-unknown-haiku -q error[E0433]: failed to resolve: use of undeclared crate or module `std` --> ~/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/os.rs:468:13 | 468 | std::ptr::null_mut(), | ^^^ use of undeclared crate or module `std` | help: consider importing one of these items | 8 + use core::ptr; | 8 + use crate::ptr; | help: if you import `ptr`, refer to it directly | 468 - std::ptr::null_mut(), 468 + ptr::null_mut(), | error[E0433]: failed to resolve: use of undeclared crate or module `std` --> ~/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/os.rs:470:13 | 470 | std::ptr::null_mut(), | ^^^ use of undeclared crate or module `std` | help: consider importing one of these items | 8 + use core::ptr; ```

Author: matthiaskrgr

std/src/sys/pal/unix/os.rs

@@ -465,9 +465,9 @@ pub fn current_exe() -> io::Result<PathBuf> {
  let mut name = vec![0; libc::PATH_MAX as usize];
  unsafe {
  let result = libc::find_path(
- std::ptr::null_mut(),
+ crate::ptr::null_mut(),
  libc::path_base_directory::B_FIND_PATH_IMAGE_PATH,
- std::ptr::null_mut(),
+ crate::ptr::null_mut(),
  name.as_mut_ptr(),
  name.len(),
  );