Add GOARCH and GOOS env vars to Go command

rust/helm-sys/Cargo.toml

@@ -12,3 +12,4 @@ links = "helm"
 
 [build-dependencies]
 bindgen.workspace = true
+snafu.workspace = true

rust/helm-sys/build.rs

@@ -1,17 +1,41 @@
-use std::{env, path::PathBuf, process::Command};
+use std::{
+    env::{self, VarError},
+    path::PathBuf,
+    process::Command,
+};
+
+use snafu::{ResultExt, Snafu};
+
+#[derive(Debug, Snafu)]
+enum Error {
+    #[snafu(display("Failed to find env var"))]
+    EnvVarNotFound { source: VarError },
+
+    #[snafu(display("Unsupported GOARCH: {arch}"))]
+    UnsupportedGoArch { arch: String },
+
+    #[snafu(display("Unsupported GOOS: {os}"))]
+    UnsupportedGoOs { os: String },
+}
 
 fn main() {
     let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
 
     println!("cargo:rerun-if-changed=go-helm-wrapper/main.go");
 
+    let goarch = get_goarch().unwrap();
+    let goos = get_goos().unwrap();
+
     let mut cmd = Command::new("go");
     cmd.arg("build")
         .args(["-buildmode", "c-archive"])
         .arg("-o")
         .arg(out_path.join("libgo-helm-wrapper.a"))
         .arg("go-helm-wrapper/main.go")
-        .env("CGO_ENABLED", "1");
+        .env("CGO_ENABLED", "1")
+        .env("GOARCH", goarch)
+        .env("GOOS", goos);
+
     cmd.status().expect("Failed to build go-helm-wrapper");
 
     let bindings = bindgen::builder()
@@ -30,3 +54,39 @@ fn main() {
         out_path.to_str().unwrap()
     );
 }
+
+fn get_goarch() -> Result<String, Error> {
+    let arch = env::var("CARGO_CFG_TARGET_ARCH").context(EnvVarNotFoundSnafu)?;
+
+    let arch = match arch.as_str() {
+        "x86" => "386",
+        "x86_64" => "amd64",
+        "mips" => "mips",
+        "powerpc" => "ppc",
+        "powerpc64" => "ppc64",
+        "arm" => "arm",
+        "aarch64" => "arm64",
+        _ => return UnsupportedGoArchSnafu { arch }.fail(),
+    };
+
+    Ok(arch.into())
+}
+
+fn get_goos() -> Result<String, Error> {
+    let os = env::var("CARGO_CFG_TARGET_OS").context(EnvVarNotFoundSnafu)?;
+
+    let os = match os.as_str() {
+        "windows" => "windows",
+        "macos" => "darwin",
+        "ios" => "darwin",
+        "linux" => "linux",
+        "android" => "android",
+        "freebsd" => "freebsd",
+        "dragonfly" => "dragonfly",
+        "openbsd" => "openbsd",
+        "netbsd" => "netbsd",
+        _ => return UnsupportedGoOsSnafu { os }.fail(),
+    };
+
+    Ok(os.into())
+}