Enable wasm32-unknown-emscripten target

Author: JohnTitor

ci/azure.yml

@@ -76,10 +76,8 @@ jobs:
         #  TARGET: wasm32-wasi
         sparc64-unknown-linux-gnu:
           TARGET: sparc64-unknown-linux-gnu
-        # Disabled because currently broken, see:
-        # https://github.com/rust-lang/libc/issues/1591
-        # wasm32-unknown-emscripten:
-        #  TARGET: wasm32-unknown-emscripten
+        wasm32-unknown-emscripten:
+          TARGET: wasm32-unknown-emscripten
         x86_64-linux-android:
           TARGET: x86_64-linux-android
         x86_64-unknown-linux-gnux32: