Pass target to compilation time

src/build/mod.rs

@@ -77,11 +77,16 @@ pub fn cargo_build_wasm(
     path: &Path,
     profile: BuildProfile,
     extra_options: &[String],
+    curr_target: &str,
 ) -> Result<()> {
     let msg = format!("{}Compiling to Wasm...", emoji::CYCLONE);
     PBAR.info(&msg);
 
     let mut cmd = Command::new("cargo");
+    cmd.env(
+        "RUSTFLAGS",
+        format!("--cfg=wasmpack_target=\"{}\"", curr_target),
+    );
     cmd.current_dir(path).arg("build").arg("--lib");
 
     if PBAR.quiet() {

src/command/build.rs

@@ -368,8 +368,12 @@ impl Build {
 
     fn step_build_wasm(&mut self) -> Result<()> {
         info!("Building wasm...");
-        build::cargo_build_wasm(&self.crate_path, self.profile.clone(), &self.extra_options)?;
-
+        build::cargo_build_wasm(
+            &self.crate_path,
+            self.profile.clone(),
+            &self.extra_options,
+            self.target.to_string().as_str(),
+        )?;
         info!(
             "wasm built at {:#?}.",
             &self