Fix warnings on linux (#879)

src/platform/linux/dlopen.rs

@@ -6,7 +6,7 @@ use std::os::raw::{c_void, c_char, c_int};
 pub const RTLD_LAZY: c_int = 0x001;
 pub const RTLD_NOW: c_int = 0x002;
 
-#[link="dl"]
+#[link(name = "dl")]
 extern {
     pub fn dlopen(filename: *const c_char, flag: c_int) -> *mut c_void;
     pub fn dlerror() -> *mut c_char;

src/platform/linux/wayland/mod.rs

@@ -16,21 +16,9 @@ mod window;
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct DeviceId;
 
-impl DeviceId {
-    pub unsafe fn dummy() -> Self {
-        DeviceId
-    }
-}
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct WindowId(usize);
 
-impl WindowId {
-    pub unsafe fn dummy() -> Self {
-        WindowId(0)
-    }
-}
-
 #[inline]
 fn make_wid(s: &Proxy<wl_surface::WlSurface>) -> WindowId {
     WindowId(s.c_ptr() as usize)