core: Allow legacy records in in a few modules

Because of macros, #[allow(structural_records]] in
extfmt, gc, os, pipes, and run. Will need a snapshot.

src/libcore/extfmt.rs

@@ -55,6 +55,9 @@
 #[forbid(deprecated_mode)];
 #[forbid(deprecated_pattern)];
 
+// Transitional
+#[allow(structural_records)]; // Macros -- needs a snapshot
+
 /*
 Syntax Extension: fmt
 

src/libcore/gc.rs

@@ -38,6 +38,8 @@ with destructors.
 // NB: transitionary, de-mode-ing.
 #[forbid(deprecated_mode)];
 #[forbid(deprecated_pattern)];
+// Transitional
+#[allow(structural_records)];
 
 use cast;
 use io;

src/libcore/os.rs

@@ -11,6 +11,7 @@
 // NB: transitionary, de-mode-ing.
 #[forbid(deprecated_mode)];
 #[forbid(deprecated_pattern)];
+#[allow(structural_records)];
 
 /*!
  * Higher-level interfaces to libc::* functions and operating system services.

src/libcore/pipes.rs

@@ -87,6 +87,9 @@ bounded and unbounded protocols allows for less code duplication.
 // re-forbid after snapshot
 #[forbid(deprecated_pattern)];
 
+// Transitional -- needs snapshot
+#[allow(structural_records)];
+
 use cmp::Eq;
 use cast::{forget, reinterpret_cast, transmute};
 use either::{Either, Left, Right};

src/libcore/run.rs

@@ -11,6 +11,7 @@
 // NB: transitionary, de-mode-ing.
 #[forbid(deprecated_mode)];
 #[forbid(deprecated_pattern)];
+#[allow(structural_records)];
 
 //! Process spawning
 use io;