Merge pull request #271 from dtolnay/windows

Support OUT_DIR located in `\\?\` path on Windows

build.rs

@@ -7,6 +7,7 @@ fn main() -> io::Result<()> {
     println!("cargo:rerun-if-changed=src/tests");
 
     println!("cargo:rustc-check-cfg=cfg(trybuild_no_target)");
+    println!("cargo:rustc-check-cfg=cfg(host_os, values(\"windows\"))");
 
     let out_dir = env::var_os("OUT_DIR").unwrap();
     let target = env::var("TARGET").ok();
@@ -15,5 +16,12 @@ fn main() -> io::Result<()> {
         Some(target) => format!(r#"Some("{}")"#, target.escape_debug()),
         None => "None".to_owned(),
     };
-    fs::write(path, value)
+    fs::write(path, value)?;
+
+    let host = env::var_os("HOST").unwrap();
+    if let Some("windows") = host.to_str().unwrap().split('-').nth(2) {
+        println!("cargo:rustc-cfg=host_os=\"windows\"");
+    }
+
+    Ok(())
 }

src/cargo.rs

@@ -183,8 +183,12 @@ fn features(project: &Project) -> Vec<String> {
 }
 
 fn target() -> Vec<&'static str> {
+    #[cfg(not(host_os = "windows"))]
     const TARGET: Option<&str> = include!(concat!(env!("OUT_DIR"), "/target"));
 
+    #[cfg(host_os = "windows")]
+    const TARGET: Option<&str> = include!(concat!(env!("OUT_DIR"), "\\target"));
+
     // When --target flag is passed, cargo does not pass RUSTFLAGS to rustc when
     // building proc-macro and build script even if the host and target triples
     // are the same. Therefore, if we always pass --target to cargo, tools such