1 files changed, 52 insertions, 0 deletions
diff --git a/library/std/build.rs b/library/std/build.rs
new file mode 100644
index 000000000..8b1a06ee7
--- /dev/null
+++ b/library/std/build.rs
@@ -0,0 +1,52 @@
+use std::env;
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+    let target = env::var("TARGET").expect("TARGET was not set");
+    if target.contains("freebsd") {
+        if env::var("RUST_STD_FREEBSD_12_ABI").is_ok() {
+            println!("cargo:rustc-cfg=freebsd12");
+        }
+    } else if target.contains("linux")
+        || target.contains("netbsd")
+        || target.contains("dragonfly")
+        || target.contains("openbsd")
+        || target.contains("solaris")
+        || target.contains("illumos")
+        || target.contains("apple-darwin")
+        || target.contains("apple-ios")
+        || target.contains("apple-watchos")
+        || target.contains("uwp")
+        || target.contains("windows")
+        || target.contains("fuchsia")
+        || (target.contains("sgx") && target.contains("fortanix"))
+        || target.contains("hermit")
+        || target.contains("l4re")
+        || target.contains("redox")
+        || target.contains("haiku")
+        || target.contains("vxworks")
+        || target.contains("wasm32")
+        || target.contains("wasm64")
+        || target.contains("asmjs")
+        || target.contains("espidf")
+        || target.contains("solid")
+        || target.contains("nintendo-3ds")
+    {
+        // These platforms don't have any special requirements.
+    } else {
+        // This is for Cargo's build-std support, to mark std as unstable for
+        // typically no_std platforms.
+        // This covers:
+        // - os=none ("bare metal" targets)
+        // - mipsel-sony-psp
+        // - nvptx64-nvidia-cuda
+        // - arch=avr
+        // - tvos (aarch64-apple-tvos, x86_64-apple-tvos)
+        // - uefi (x86_64-unknown-uefi, i686-unknown-uefi)
+        // - JSON targets
+        // - Any new targets that have not been explicitly added above.
+        println!("cargo:rustc-cfg=feature=\"restricted-std\"");
+    }
+    println!("cargo:rustc-env=STD_ENV_ARCH={}", env::var("CARGO_CFG_TARGET_ARCH").unwrap());
+    println!("cargo:rustc-cfg=backtrace_in_libstd");
+}