pmt: scripts: update header generator script

build/bash/gen-header

@@ -14,13 +14,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-[ -z ${NDK_ROOT_DIR} ] \
-&& echo "Please set NDK_ROOT_DIR variable!" \
-&& exit 1
+[ -z ${NDK_ROOT_DIR} ] && \
+    {
+        echo "Please set NDK_ROOT_DIR variable!"
+        exit 1
+    }
 
-[ -z ${NDK_PROJECT_PATH} ] \
-&& echo "Please set NDK_PROJECT_PATH variable!" \
-&& exit 1
+[ -z ${NDK_PROJECT_PATH} ] && \
+    {
+        echo "Please set NDK_PROJECT_PATH variable!"
+        exit 1
+    }
 
 CXX_IS="${NDK_ROOT_DIR}/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android21-clang++"
 CXX_VERS=$(${CXX_IS} --version | head -n 1)