bugfix: Use get_errno instead of last_os_error

According to @stlankes this causes strange errors in Hermit proper.

Signed-off-by: John Nunley <dev@notgull.net>

Cargo.toml

@@ -46,7 +46,7 @@ features = [
 ]
 
 [target.'cfg(target_os = "hermit")'.dependencies.hermit-abi]
-version = "0.3.8"
+version = "0.3.9"
 
 [dev-dependencies]
 easy-parallel = "3.1.0"

src/poll.rs

@@ -475,7 +475,9 @@ mod syscall {
         let fd = unsafe { hermit_abi::eventfd(count, 0) };
 
         if fd == -1 {
-            Err(io::Error::last_os_error())
+            Err(io::Error::from_raw_os_error(unsafe {
+                hermit_abi::get_errno()
+            }))
         } else {
             Ok(unsafe { OwnedFd::from_raw_fd(fd) })
         }
@@ -611,7 +613,9 @@ mod syscall {
     #[inline]
     fn cvt(len: isize) -> io::Result<usize> {
         if len == -1 {
-            Err(io::Error::last_os_error())
+            Err(io::Error::from_raw_os_error(unsafe {
+                hermit_abi::get_errno()
+            }))
         } else {
             Ok(len as usize)
         }