37 lines
1.2 KiB
Rust
37 lines
1.2 KiB
Rust
use std::env;
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use std::process::Command;
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use std::str;
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// The rustc-cfg strings below are *not* public API. Please let us know by
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// opening a GitHub issue if your build environment requires some way to enable
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// these cfgs other than by executing our build script.
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fn main() {
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let minor = match rustc_minor_version() {
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Some(minor) => minor,
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None => return,
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};
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// Underscore const names stabilized in Rust 1.37:
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// https://blog.rust-lang.org/2019/08/15/Rust-1.37.0.html#using-unnamed-const-items-for-macros
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if minor >= 37 {
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println!("cargo:rustc-cfg=underscore_consts");
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}
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// The ptr::addr_of! macro stabilized in Rust 1.51:
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// https://blog.rust-lang.org/2021/03/25/Rust-1.51.0.html#stabilized-apis
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if minor >= 51 {
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println!("cargo:rustc-cfg=ptr_addr_of");
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}
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}
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fn rustc_minor_version() -> Option<u32> {
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let rustc = env::var_os("RUSTC")?;
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let output = Command::new(rustc).arg("--version").output().ok()?;
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let version = str::from_utf8(&output.stdout).ok()?;
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let mut pieces = version.split('.');
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if pieces.next() != Some("rustc 1") {
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return None;
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}
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pieces.next()?.parse().ok()
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}
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