split-select: Fix rules generated for anydpi density

Change-Id: I9de569ca9a76eb22df4d0e178df847ba1c7d0b01
diff --git a/tools/split-select/Android.mk b/tools/split-select/Android.mk
index dc48ea8..968d22b 100644
--- a/tools/split-select/Android.mk
+++ b/tools/split-select/Android.mk
@@ -34,7 +34,8 @@
 testSources := \
     Grouper_test.cpp \
     Rule_test.cpp \
-    RuleGenerator_test.cpp
+    RuleGenerator_test.cpp \
+    TestRules.cpp
 
 cIncludes := \
     external/zlib \