On linux without X11 or Wayland, reduced the panic message to a single line (#681)

CHANGELOG.md

@@ -18,6 +18,7 @@
 - Implemented the `Debug` trait for `Window`, `EventsLoop`, `EventsLoopProxy` and `WindowBuilder`.
 - On X11, now a `Resized` event will always be generated after a DPI change to ensure the window's logical size is consistent with the new DPI.
 - Added further clarifications to the DPI docs.
+- On Linux, if neither X11 nor Wayland manage to initialize, the corresponding panic now consists of a single line only.
 
 # Version 0.17.2 (2018-08-19)
 

src/platform/linux/mod.rs

@@ -430,10 +430,7 @@ impl EventsLoop {
         };
 
         let err_string = format!(
-r#"Failed to initialize any backend!
-    Wayland status: {:#?}
-    X11 status: {:#?}
-"#,
+            "Failed to initialize any backend! Wayland status: {:?} X11 status: {:?}",
             wayland_err,
             x11_err,
         );