diff --git a/tools/emulator/system/gps/Android.mk b/tools/emulator/system/gps/Android.mk
index add551d02..41bdc6440 100644
--- a/tools/emulator/system/gps/Android.mk
+++ b/tools/emulator/system/gps/Android.mk
@@ -12,6 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+# We're moving the emulator-specific platform libs to
+# development.git/tools/emulator/. The following test is to ensure
+# smooth builds even if the tree contains both versions.
+#
+ifndef BUILD_EMULATOR_GPS_MODULE
+BUILD_EMULATOR_GPS_MODULE := true
+
 LOCAL_PATH := $(call my-dir)
 
 ifneq ($(TARGET_PRODUCT),sim)
@@ -27,3 +35,5 @@ LOCAL_MODULE := gps.goldfish
 LOCAL_MODULE_TAGS := debug
 include $(BUILD_SHARED_LIBRARY)
 endif
+
+endif # BUILD_EMULATOR_GPS_MODULE
diff --git a/tools/emulator/system/qemu-props/Android.mk b/tools/emulator/system/qemu-props/Android.mk
index dd15824da..1bdbf684a 100644
--- a/tools/emulator/system/qemu-props/Android.mk
+++ b/tools/emulator/system/qemu-props/Android.mk
@@ -16,6 +16,13 @@
 # that should only run in the emulator.
 #
 
+# We're moving the emulator-specific platform libs to
+# development.git/tools/emulator/. The following test is to ensure
+# smooth builds even if the tree contains both versions.
+#
+ifndef BUILD_EMULATOR_QEMU_PROPS
+BUILD_EMULATOR_QEMU_PROPS := true
+
 LOCAL_PATH := $(call my-dir)
 
 ifneq ($(TARGET_PRODUCT),sim)
@@ -33,3 +40,5 @@ LOCAL_MODULE_TAGS := debug
 include $(BUILD_EXECUTABLE)
 
 endif # TARGET_PRODUCT != sim
+
+endif # BUILD_EMULATOR_QEMU_PROPS
diff --git a/tools/emulator/system/qemud/Android.mk b/tools/emulator/system/qemud/Android.mk
index a186c73de..5666a74a1 100644
--- a/tools/emulator/system/qemud/Android.mk
+++ b/tools/emulator/system/qemud/Android.mk
@@ -1,5 +1,12 @@
 # Copyright 2008 The Android Open Source Project
 
+# We're moving the emulator-specific platform libs to
+# development.git/tools/emulator/. The following test is to ensure
+# smooth builds even if the tree contains both versions.
+#
+ifndef BUILD_EMULATOR_QEMUD
+BUILD_EMULATOR_QEMUD := true
+
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
@@ -14,3 +21,5 @@ LOCAL_MODULE:= qemud
 LOCAL_MODULE_TAGS := debug
 
 include $(BUILD_EXECUTABLE)
+
+endif # BUILD_EMULATOR_QEMUD
\ No newline at end of file
diff --git a/tools/emulator/system/sensors/Android.mk b/tools/emulator/system/sensors/Android.mk
index 7533f7365..9b0e83d86 100644
--- a/tools/emulator/system/sensors/Android.mk
+++ b/tools/emulator/system/sensors/Android.mk
@@ -12,6 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+# We're moving the emulator-specific platform libs to
+# development.git/tools/emulator/. The following test is to ensure
+# smooth builds even if the tree contains both versions.
+#
+ifndef BUILD_EMULATOR_SENSORS_MODULE
+BUILD_EMULATOR_SENSORS_MODULE := true
+
 LOCAL_PATH := $(call my-dir)
 
 ifneq ($(TARGET_PRODUCT),sim)
@@ -26,3 +34,5 @@ LOCAL_MODULE := sensors.goldfish
 LOCAL_MODULE_TAGS := debug
 include $(BUILD_SHARED_LIBRARY)
 endif
+
+endif # BUILD_EMULATOR_SENSORS_MODULE