Add structopt dependency in version 0.3.7

This patch series replaces argparse with structopt in the argument
handling code. As a first step, we need structopt as a dependency.

Import subrepo structopt/:structopt at efbdda4753592e27bc430fb01f7b9650b2f3174d
Import subrepo bitflags/:bitflags at 30668016aca6bd3b02c766e8347e0b4080d4c296
Import subrepo clap/:clap at 784524f7eb193e35f81082cc69454c8c21b948f7
Import subrepo heck/:heck at 093d56fbf001e1506e56dbfa38631d99b1066df1
Import subrepo proc-macro-error/:proc-macro-error at 6c4cfe79a622c5de8ae68557993542be46eacae2
Import subrepo proc-macro2/:proc-macro2 at d5d48eddca4566e5438e8a2cbed4a74e049544de
Import subrepo quote/:quote at 727436c6c137b20f0f34dde5d8fda2679b9747ad
Import subrepo rustversion/:rustversion at 0c5663313516263059ce9059ef81fc7a1cf655ca
Import subrepo syn-mid/:syn-mid at 5d3d85414a9e6674e1857ec22a87b96e04a6851a
Import subrepo syn/:syn at e87c27e87f6f4ef8919d0372bdb056d53ef0d8f3
Import subrepo textwrap/:textwrap at abcd618beae3f74841032aa5b53c1086b0a57ca2
Import subrepo unicode-segmentation/:unicode-segmentation at 637c9874c4fe0c205ff27787faf150a40295c6c3
Import subrepo unicode-width/:unicode-width at 3033826f8bf05e82724140a981d5941e48fce393
Import subrepo unicode-xid/:unicode-xid at 4baae9fffb156ba229665b972a9cd5991787ceb7

1 files changed, 138 insertions, 0 deletions

diff --git a/rustversion/README.md b/rustversion/README.md
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+Compiler version cfg
+====================
+
+[![Build Status](https://api.travis-ci.com/dtolnay/rustversion.svg?branch=master)](https://travis-ci.com/dtolnay/rustversion)
+[![Latest Version](https://img.shields.io/crates/v/rustversion.svg)](https://crates.io/crates/rustversion)
+[![Rust Documentation](https://img.shields.io/badge/api-rustdoc-blue.svg)](https://docs.rs/rustversion)
+
+This crate provides macros for conditional compilation according to rustc
+compiler version, analogous to [`#[cfg(...)]`][cfg] and
+[`#[cfg_attr(...)]`][cfg_attr].
+
+[cfg]: https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute
+[cfg_attr]: https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute
+
+```toml
+[dependencies]
+rustversion = "1.0"
+```
+
+<br>
+
+## Selectors
+
+- <b>`#[rustversion::stable]`</b>
+  —<br>
+  True on any stable compiler.
+
+- <b>`#[rustversion::stable(1.34)]`</b>
+  —<br>
+  True on exactly the specified stable compiler.
+
+- <b>`#[rustversion::beta]`</b>
+  —<br>
+  True on any beta compiler.
+
+- <b>`#[rustversion::nightly]`</b>
+  —<br>
+  True on any nightly compiler or dev build.
+
+- <b>`#[rustversion::nightly(2019-01-01)]`</b>
+  —<br>
+  True on exactly one nightly.
+
+- <b>`#[rustversion::since(1.34)]`</b>
+  —<br>
+  True on that stable release and any later compiler, including beta and
+  nightly.
+
+- <b>`#[rustversion::since(2019-01-01)]`</b>
+  —<br>
+  True on that nightly and all newer ones.
+
+- <b>`#[rustversion::before(`</b><i>version or date</i><b>`)]`</b>
+  —<br>
+  Negative of *#[rustversion::since(...)]*.
+
+- <b>`#[rustversion::not(`</b><i>selector</i><b>`)]`</b>
+  —<br>
+  Negative of any selector; for example *#[rustversion::not(nightly)]*.
+
+- <b>`#[rustversion::any(`</b><i>selectors...</i><b>`)]`</b>
+  —<br>
+  True if any of the comma-separated selectors is true; for example
+  *#[rustversion::any(stable, beta)]*.
+
+- <b>`#[rustversion::all(`</b><i>selectors...</i><b>`)]`</b>
+  —<br>
+  True if all of the comma-separated selectors are true; for example
+  *#[rustversion::all(since(1.31), before(1.34))]*.
+
+- <b>`#[rustversion::attr(`</b><i>selector</i><b>`, `</b><i>attribute</i><b>`)]`</b>
+  —<br>
+  For conditional inclusion of attributes; analogous to `cfg_attr`.
+
+<br>
+
+## Use cases
+
+Providing additional trait impls as types are stabilized in the standard library
+without breaking compatibility with older compilers; in this case Pin\<P\>
+stabilized in [Rust 1.33][pin]:
+
+[pin]: https://blog.rust-lang.org/2019/02/28/Rust-1.33.0.html#pinning
+
+```rust
+#[rustversion::since(1.33)]
+use std::pin::Pin;
+
+#[rustversion::since(1.33)]
+impl<P: MyTrait> MyTrait for Pin<P> {
+    /* ... */
+}
+```
+
+Similar but for language features; the ability to control alignment greater than
+1 of packed structs was stabilized in [Rust 1.33][packed].
+
+[packed]: https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1330-2019-02-28
+
+```rust
+#[rustversion::attr(before(1.33), repr(packed))]
+#[rustversion::attr(since(1.33), repr(packed(2)))]
+struct Six(i16, i32);
+
+fn main() {
+    println!("{}", std::mem::align_of::<Six>());
+}
+```
+
+Augmenting code with `const` as const impls are stabilized in the standard
+library. This use of `const` as an attribute is recognized as a special case by
+the rustversion::attr macro.
+
+```rust
+use std::time::Duration;
+
+#[rustversion::attr(since(1.32), const)]
+fn duration_as_days(dur: Duration) -> u64 {
+    dur.as_secs() / 60 / 60 / 24
+}
+```
+
+<br>
+
+#### License
+
+<sup>
+Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
+2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
+</sup>
+
+<br>
+
+<sub>
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in this crate by you, as defined in the Apache-2.0 license, shall
+be dual licensed as above, without any additional terms or conditions.
+</sub>