Auto merge of #13723 - Manishearth:resync, r=bholley

Regen bindings, warning fix

The warning only happens on the latest stable (which we use in the incubator), so there's an `#[allow()]` there for now as well.

Don't signal r+ to bors, I'll do that myself when the incubator side lands.

r? @bholley

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components/style/properties/gecko.mako.rs

@@ -1984,11 +1984,14 @@ clip-path
 
     ${impl_coord_copy('column_width', 'mColumnWidth')}
 
+    #[allow(unused_unsafe)]
     pub fn set_column_count(&mut self, v: longhands::column_count::computed_value::T) {
         use gecko_bindings::structs::{NS_STYLE_COLUMN_COUNT_AUTO, nsStyleColumn_kMaxColumnCount};
 
         self.gecko.mColumnCount = match v.0 {
-            Some(number) => cmp::min(number, nsStyleColumn_kMaxColumnCount),
+            Some(number) => unsafe {
+                cmp::min(number, nsStyleColumn_kMaxColumnCount)
+            },
             None => NS_STYLE_COLUMN_COUNT_AUTO
         };
     }