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