Add copyright notice to build-prebuilts.sh

Bug: 111579848
Test: n/a
Change-Id: I73f41e1a08b1f08ecf4e8017ecccf020d269939b
diff --git a/build-prebuilts.sh b/build-prebuilts.sh
index 3270e1b..a2bbdc7 100755
--- a/build-prebuilts.sh
+++ b/build-prebuilts.sh
@@ -1,5 +1,19 @@
 #!/bin/bash -ex
 
+# Copyright 2018 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 if [ -z "${OUT_DIR}" ]; then
     echo Must set OUT_DIR
     exit 1