Fix Path::is_absolute on Hermit

Author: mkroening

std/src/path.rs

@@ -2327,7 +2327,9 @@ impl Path {
             // FIXME: Allow Redox prefixes
             self.has_root() || has_redox_scheme(self.as_u8_slice())
         } else {
-            self.has_root() && (cfg!(any(unix, target_os = "wasi")) || self.prefix().is_some())
+            self.has_root()
+                && (cfg!(any(unix, target_os = "hermit", target_os = "wasi"))
+                    || self.prefix().is_some())
         }
     }