Remove the need to find Android.mk files via directory symlinks

Bug: 64397960
Test: m -j
Change-Id: I5b77dd654dfced63900913c447b5448b632158d7
diff --git a/tools/Android.mk b/tools/Android.mk
index 9073ac3..c05d681 100644
--- a/tools/Android.mk
+++ b/tools/Android.mk
@@ -16,4 +16,8 @@
 
 LOCAL_PATH := $(call my-dir)
 
+# Only if this Android.mk was included not by a symlink should it be used.
+# This facilitates the transition away from symlinks: b/64397960
+ifeq ($(LOCAL_PATH),build/make/tools)
 include $(call all-makefiles-under,$(LOCAL_PATH))
+endif