Revert "Remove @__identity rule."

src/lib.rs

@@ -82,7 +82,7 @@ macro_rules! cfg_if {
             $( $yes , )?
             not(any( $( $no ),* ))
         ))]
-        $( $tokens )*
+        $crate::cfg_if! { @__identity $( $tokens )* }
 
         // Recurse to emit all other items in `$rest`, and when we do so add all
         // our `$yes` matchers to the list of `$no` matchers as future emissions
@@ -92,6 +92,12 @@ macro_rules! cfg_if {
             $( $rest , )*
         }
     };
+
+    // Internal macro to make __apply work out right for different match types,
+    // because of how macros match/expand stuff.
+    (@__identity $( $tokens:tt )* ) => {
+        $( $tokens )*
+    };
 }
 
 #[cfg(test)]