Add musl support

Signed-off-by: Kate Goldenring <[email protected]>

Author: kate-goldenring

Cargo.toml

@@ -16,7 +16,7 @@ spin-expressions = { git = "https://github.com/fermyon/spin", tag = "v2.6.0" }
 spin-trigger = { git = "https://github.com/fermyon/spin", tag = "v2.6.0" }
 spin-telemetry = { git = "https://github.com/fermyon/spin", tag = "v2.6.0" }
 tokio = { version = "1.37", features = ["full"] }
-paho-mqtt = { version = "0.12.3", default-features = false, features = [
+paho-mqtt = { version = "0.12.3", features = [
     "vendored-ssl",
 ] }
 wasmtime = { version = "21.0.1" }

build.rs

@@ -0,0 +1,10 @@
+fn is_musl() -> bool {
+    std::env::var("CARGO_CFG_TARGET_ENV").unwrap() == "musl"
+}
+
+fn main() {
+    if is_musl() {
+        // Required for OpenSSL with musl
+        println!("cargo:rustc-link-arg=-lc");
+    }
+}