Merging upstream version 1.71.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 26 insertions, 6 deletions

diff --git a/vendor/memoffset/README.md b/vendor/memoffset/README.md
index e297b33d5..b0bfd1014 100644
--- a/vendor/memoffset/README.md
+++ b/vendor/memoffset/README.md
@@ -7,6 +7,7 @@ C-Like `offset_of` functionality for Rust structs.
 Introduces the following macros:
  * `offset_of!` for obtaining the offset of a member of a struct.
  * `offset_of_tuple!` for obtaining the offset of a member of a tuple. (Requires Rust 1.20+)
+ * `offset_of_union!` for obtaining the offset of a member of a union.
  * `span_of!` for obtaining the range that a field, or fields, span.
 
 `memoffset` works under `no_std` environments.
@@ -16,7 +17,7 @@ Add the following dependency to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-memoffset = "0.7"
+memoffset = "0.8"
 ```
 
 These versions will compile fine with rustc versions greater or equal to 1.19.
@@ -45,21 +46,40 @@ fn main() {
 }
 ```
 
-## Feature flags ##
+## Usage in constants ##
+`memoffset` has support for compile-time `offset_of!` on rust>=1.65, or on older nightly compilers.
 
-### Usage in constants ###
-`memoffset` has **experimental** support for compile-time `offset_of!` on a nightly compiler.
+### Usage on stable Rust ###
+Constant evaluation is automatically enabled and avilable on stable compilers starting with rustc 1.65.
 
-In order to use it, you must enable the `unstable_const` crate feature and several compiler features.
+This is an incomplete implementation with one caveat:
+Due to dependence on [`#![feature(const_refs_to_cell)]`](https://github.com/rust-lang/rust/issues/80384), you cannot get the offset of a `Cell` field in a const-context.
+
+This means that if need to get the offset of a cell, you'll have to remain on nightly for now.
+
+### Usage on recent nightlies ###
+
+If you're using a new-enough nightly and you require the ability to get the offset of a `Cell`,
+you'll have to enable the `unstable_const` cargo feature, as well as enabling `const_refs_to_cell` in your crate root.
+
+Do note that `unstable_const` is an unstable feature that is set to be removed in a future version of `memoffset`.
 
 Cargo.toml:
 ```toml
 [dependencies.memoffset]
-version = "0.7"
+version = "0.8"
 features = ["unstable_const"]
 ```
 
 Your crate root: (`lib.rs`/`main.rs`)
 ```rust,ignore
+#![feature(const_refs_to_cell)]
+```
+
+### Usage on older nightlies ###
+In order to use it on an older nightly compiler, you must enable the `unstable_const` crate feature and several compiler features.
+
+Your crate root: (`lib.rs`/`main.rs`)
+```rust,ignore
 #![feature(const_ptr_offset_from, const_refs_to_cell)]
 ```