blob: 9b13376779f65a459b8d58e3f11d4745b5945b66 [file] [log] [blame]
use std::env;
use std::process::Command;
use std::str;
fn main() {
let rustc_minor_ver =
rustc_minor_version().expect("Failed to get rustc version");
let rustc_dep_of_std =
std::env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
let align_cargo_feature = std::env::var("CARGO_FEATURE_ALIGN").is_ok();
// Rust >= 1.15 supports private module use:
if rustc_minor_ver >= 15 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_priv_mod_use");
}
// Rust >= 1.19 supports unions:
if rustc_minor_ver >= 19 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_union");
}
// Rust >= 1.24 supports const mem::size_of:
if rustc_minor_ver >= 24 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_const_size_of");
}
// Rust >= 1.25 supports repr(align):
if rustc_minor_ver >= 25 || rustc_dep_of_std || align_cargo_feature {
println!("cargo:rustc-cfg=libc_align");
}
// Rust >= 1.30 supports `core::ffi::c_void`, so libc can just re-export it.
// Otherwise, it defines an incompatible type to retaining
// backwards-compatibility.
if rustc_minor_ver >= 30 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_core_cvoid");
}
// Rust >= 1.33 supports repr(packed(N))
if rustc_minor_ver >= 33 || rustc_dep_of_std {
println!("cargo:rustc-cfg=libc_packedN");
}
}
fn rustc_minor_version() -> Option<u32> {
macro_rules! otry {
($e:expr) => {
match $e {
Some(e) => e,
None => return None,
}
};
}
let rustc = otry!(env::var_os("RUSTC"));
let output = otry!(Command::new(rustc).arg("--version").output().ok());
let version = otry!(str::from_utf8(&output.stdout).ok());
let mut pieces = version.split('.');
if pieces.next() != Some("rustc 1") {
return None;
}
otry!(pieces.next()).parse().ok()
}