Add new Android.mk to handle repo move

We're moving the platform/build repository down a level, then symlinking
the directories and necessary files back into build/. So if we're still
in build/, keep searching for Android.mk files, otherwise stop, since
they'll be found through the symlinks.

Bug: 28001743
Change-Id: Ieea6e3b1fca265b548395c6af148ebb4efa43b0f
diff --git a/Android.mk b/Android.mk
new file mode 100644
index 0000000..a1455d4
--- /dev/null
+++ b/Android.mk
@@ -0,0 +1,8 @@
+LOCAL_PATH := $(call my-dir)
+
+# We're relocating the build project to a subdirectory, then using symlinks
+# to expose the subdirectories where they used to be. If the manifest hasn't
+# been updated, we need to include all the subdirectories.
+ifeq ($(LOCAL_PATH),build)
+include $(call first-makefiles-under,$(LOCAL_PATH))
+endif