class/cargo: Handle case when host and target has same arch

When we have same architecture for the host and target, we need to
properly handle the native and target case as Rust cannot differentiate
both.

Fixes: #70.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>

classes/cargo.bbclass

@@ -48,14 +48,18 @@ CARGO_BUILD_FLAGS = "\
 "
 
 create_cargo_config() {
-    echo > ${CARGO_HOME}/config
-    echo "[target.${RUST_BUILD}]" >> ${CARGO_HOME}/config
-    echo "linker = '${WRAPPER_DIR}/linker-native-wrapper.sh'" >> ${CARGO_HOME}/config
-
     if [ "${RUST_BUILD}" != "${RUST_TARGET}" ]; then
+        echo > ${CARGO_HOME}/config
+        echo "[target.${RUST_BUILD}]" >> ${CARGO_HOME}/config
+        echo "linker = '${WRAPPER_DIR}/linker-native-wrapper.sh'" >> ${CARGO_HOME}/config
+
         echo >> ${CARGO_HOME}/config
         echo "[target.${RUST_TARGET}]" >> ${CARGO_HOME}/config
         echo "linker = '${WRAPPER_DIR}/linker-wrapper.sh'" >> ${CARGO_HOME}/config
+    else
+        echo > ${CARGO_HOME}/config
+        echo "[target.${RUST_TARGET}]" >> ${CARGO_HOME}/config
+        echo "linker = '${WRAPPER_DIR}/linker-wrapper.sh'" >> ${CARGO_HOME}/config
     fi
 
     echo >> ${CARGO_HOME}/config