1 files changed, 125 insertions, 0 deletions
diff --git a/build/rust/bitflags/lib.rs b/build/rust/bitflags/lib.rs
new file mode 100644
index 0000000000..408d279b9f
--- /dev/null
+++ b/build/rust/bitflags/lib.rs
@@ -0,0 +1,125 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub use bitflags::*;
+
+// Copy of the macro from bitflags 1.3.2, with the implicit derives
+// removed, because in 2.0, they're expected to be explicitly given
+// in the macro invocation. And because bitflags 1.3.2 itself always
+// adds an impl Debug, we need to remove #[derive(Debug)] from what
+// is passed in, which is what the __impl_bitflags_remove_derive_debug
+// macro does.
+#[macro_export(local_inner_macros)]
+macro_rules! bitflags {
+    (
+        $(#[$($outer:tt)+])*
+        $vis:vis struct $BitFlags:ident: $T:ty {
+            $(
+                $(#[$inner:ident $($args:tt)*])*
+                const $Flag:ident = $value:expr;
+            )*
+        }
+
+        $($t:tt)*
+    ) => {
+        __impl_bitflags_remove_derive_debug! {
+            $(#[$($outer)+])*
+
+            $vis struct $BitFlags {
+                bits: $T,
+            }
+        }
+
+        __impl_bitflags! {
+            $BitFlags: $T {
+                $(
+                    $(#[$inner $($args)*])*
+                    $Flag = $value;
+                )*
+            }
+        }
+
+        impl $BitFlags {
+            /// Convert from underlying bit representation, preserving all
+            /// bits (even those not corresponding to a defined flag).
+            #[inline]
+            pub const fn from_bits_retain(bits: $T) -> Self {
+                Self { bits }
+            }
+        }
+
+        bitflags! {
+            $($t)*
+        }
+    };
+    () => {};
+}
+
+#[macro_export(local_inner_macros)]
+#[doc(hidden)]
+macro_rules! __impl_bitflags_remove_derive_debug {
+    (
+        $(@ $(#[$keep_outer:meta])* @)?
+        #[derive(@ $($keep_derives:ident),+ @)]
+        $(#[$($other_outer:tt)+])*
+        $vis:vis struct $BitFlags:ident { $($t:tt)* }
+    ) => {
+        __impl_bitflags_remove_derive_debug! {
+            @ $($(#[$keep_outer])*)? #[derive($($keep_derives),+)] @
+            $(#[$($other_outer)+])*
+            $vis struct $BitFlags { $($t)* }
+        }
+    };
+    (
+        $(@ $(#[$keep_outer:meta])* @)?
+        #[derive($(@ $($keep_derives:ident),+ @)? Debug $(,$derives:ident)*)]
+        $(#[$($other_outer:tt)+])*
+        $vis:vis struct $BitFlags:ident { $($t:tt)* }
+    ) => {
+        __impl_bitflags_remove_derive_debug! {
+            @ $($(#[$keep_outer])*)? @
+            #[derive($(@ $($keep_derives),+ @)? $($derives),*)]
+            $(#[$($other_outer)+])*
+            $vis struct $BitFlags { $($t)* }
+        }
+    };
+    (
+        $(@ $(#[$keep_outer:meta])* @)?
+        #[derive($(@ $($keep_derives:ident),+ @)? $derive:ident $(,$derives:ident)*)]
+        $(#[$($other_outer:tt)+])*
+        $vis:vis struct $BitFlags:ident { $($t:tt)* }
+    ) => {
+        __impl_bitflags_remove_derive_debug! {
+            @ $($(#[$keep_outer])*)? @
+            #[derive(@ $($($keep_derives,)+)? $derive @ $($derives),*)]
+            $(#[$($other_outer)+])*
+            $vis struct $BitFlags { $($t)* }
+        }
+    };
+    (
+        $(@ $(#[$keep_outer:meta])* @)?
+        #[$outer:meta]
+        $(#[$($other_outer:tt)+])*
+        $vis:vis struct $BitFlags:ident { $($t:tt)* }
+    ) => {
+        __impl_bitflags_remove_derive_debug! {
+            @ $($(#[$keep_outer])*)? #[$outer] @
+            $(#[$($other_outer)+])*
+            $vis struct $BitFlags { $($t)* }
+        }
+    };
+    (
+        @ $(#[$keep_outer:meta])* @
+        $vis:vis struct $BitFlags:ident { $($t:tt)* }
+    ) => {
+        $(#[$keep_outer])*
+        $vis struct $BitFlags { $($t)* }
+    };
+}