diff --git a/core/config.mk b/core/config.mk
index 39dbf55..713760f 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -110,6 +110,9 @@
 # Various mappings to avoid hard-coding paths all over the place
 include $(BUILD_SYSTEM)/pathmap.mk
 
+# Allow projects to define their own globally-available variables
+include $(BUILD_SYSTEM)/project_definitions.mk
+
 # ###############################################################
 # Build system internal files
 # ###############################################################
diff --git a/core/project_definitions.mk b/core/project_definitions.mk
new file mode 100644
index 0000000..68572eb
--- /dev/null
+++ b/core/project_definitions.mk
@@ -0,0 +1,24 @@
+#
+# Copyright (C) 2018 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.
+#
+
+#
+# Allow projects to define their own globally-available variables.
+#
+
+#
+# Include definitions for Support Library modules, if present.
+#
+-include prebuilts/sdk/current/support/definitions.mk