fix: build on haiku

Author: SteveLauC

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(),
  );