Add build task for cts_root.

This adds the configuration necessary to allow the cts_root
test suite to be built.

Bug: 162933947
Test: m cts_root
Merged-In: I4732bf82d3cedc77e30d7fa5eff285d382992853
Change-Id: I4732bf82d3cedc77e30d7fa5eff285d382992853

core/main.mk

@@ -83,6 +83,8 @@ $(shell mkdir -p $(EMPTY_DIRECTORY) && rm -rf $(EMPTY_DIRECTORY)/*)
 -include test/vts/tools/vts-core-tradefed/build/config.mk
 # CSUITE-specific config.
 -include test/app_compat/csuite/tools/build/config.mk
+# CTS-Root-specific config.
+-include test/cts-root/tools/build/config.mk
 
 # Clean rules
 .PHONY: clean-dex-files

core/tasks/cts_root.mk

@@ -0,0 +1,25 @@
+# Copyright (C) 2021 The Android Open Source Project
+#
+# 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.
+
+ifneq ($(wildcard test/cts-root/README.md),)
+test_suite_name := cts_root
+test_suite_tradefed := cts-root-tradefed
+test_suite_readme := test/cts-root/README.md
+
+include $(BUILD_SYSTEM)/tasks/tools/compatibility.mk
+
+.PHONY: cts_root
+cts_root: $(compatibility_zip)
+$(call dist-for-goals, cts_root, $(compatibility_zip))
+endif