Propagate error from EventLoop creation

Inner panics could make it hard to trouble shoot the issues and for some
users ints not desirable.

The inner panics were left only when they are used to `assert!` during
development.

src/platform_impl/orbital/mod.rs

@@ -1,6 +1,8 @@
 #![cfg(target_os = "redox")]
 
+use std::fmt::{self, Display, Formatter};
 use std::str;
+use std::sync::Arc;
 
 use crate::dpi::{PhysicalPosition, PhysicalSize};
 
@@ -176,13 +178,18 @@ impl<'a> fmt::Display for WindowProperties<'a> {
     }
 }
 
-#[derive(Default, Clone, Debug)]
-pub struct OsError;
+#[derive(Clone, Debug)]
+pub struct OsError(Arc<syscall::Error>);
+
+impl OsError {
+    fn new(error: syscall::Error) -> Self {
+        Self(Arc::new(error))
+    }
+}
 
-use std::fmt::{self, Display, Formatter};
 impl Display for OsError {
     fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), fmt::Error> {
-        write!(fmt, "Redox OS Error")
+        self.0.fmt(fmt)
     }
 }