auto merge of #16667 : retep998/rust/master, r=pcwalton

Author: bors

src/librustrt/unwind.rs

@@ -402,8 +402,11 @@ pub mod eabi {
     use libunwind as uw;
     use libc::{c_void, c_int};
 
+    #[repr(C)]
     struct EXCEPTION_RECORD;
+    #[repr(C)]
     struct CONTEXT;
+    #[repr(C)]
     struct DISPATCHER_CONTEXT;
 
     #[repr(C)]