Fix switchless samplecode link error
diff --git a/samplecode/switchless/app/build.rs b/samplecode/switchless/app/build.rs
index 65a322e..fd8807d 100644
--- a/samplecode/switchless/app/build.rs
+++ b/samplecode/switchless/app/build.rs
@@ -28,6 +28,7 @@
     println!("cargo:rustc-link-lib=static=Enclave_u");
 
     println!("cargo:rustc-link-search=native={}/lib64", sdk_dir);
+    println!("cargo:rustc-link-lib=static=sgx_uswitchless");
     match is_sim.as_ref() {
         "SW" => println!("cargo:rustc-link-lib=dylib=sgx_urts_sim"),
         "HW" => println!("cargo:rustc-link-lib=dylib=sgx_urts"),
diff --git a/samplecode/switchless/app/src/main.rs b/samplecode/switchless/app/src/main.rs
index 8876218..4ccb4c1 100644
--- a/samplecode/switchless/app/src/main.rs
+++ b/samplecode/switchless/app/src/main.rs
@@ -15,9 +15,7 @@
 // specific language governing permissions and limitations
 // under the License..
 
-#![feature(link_args)]
 #![allow(unused_attributes)]
-#![link_args = "-Wl,--whole-archive -lsgx_uswitchless -Wl,--no-whole-archive"]
 
 extern crate sgx_types;
 extern crate sgx_urts;