Rollup merge of #115984 - hermit-os:fuse, r=m-ou-se

extending filesystem support for Hermit

Extending `std` to create, change and read a directory for Hermit.

Hermit is a tier 3 platform and this PR changes only files, wich are related to the tier 3 platform.

Author: matthiaskrgr

Diff for: library/std/src/sys/pal/hermit/fd.rs

@@ -48,6 +48,11 @@ impl FileDesc {
     pub fn set_nonblocking(&self, _nonblocking: bool) -> io::Result<()> {
         unsupported()
     }
+
+    pub fn fstat(&self, stat: *mut abi::stat) -> io::Result<()> {
+        cvt(unsafe { abi::fstat(self.fd.as_raw_fd(), stat) })?;
+        Ok(())
+    }
 }
 
 impl<'a> Read for &'a FileDesc {