Import crc32fast-1.2.1
Change-Id: Ibca0149152d4553ed96af60d79699279e8107104
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..563cb21
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,35 @@
+use std::env;
+use std::process::Command;
+use std::str;
+
+fn main() {
+ println!("cargo:rerun-if-changed=build.rs");
+
+ let minor = match rustc_minor_version() {
+ Some(n) => n,
+ None => return,
+ };
+
+ if minor >= 27 {
+ println!("cargo:rustc-cfg=crc32fast_stdarchx86");
+ }
+}
+
+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()
+}