Disable dexpreopt for unbundled build.

Change-Id: Iad0cc41cfad2533703a0dddad743720c43ddb667
diff --git a/core/java_library.mk b/core/java_library.mk
index abc4728..dbf6981 100644
--- a/core/java_library.mk
+++ b/core/java_library.mk
@@ -30,10 +30,12 @@
 LOCAL_INTERMEDIATE_TARGETS += $(common_javalib.jar)
 
 ifeq (true,$(WITH_DEXPREOPT))
+ifeq (,$(TARGET_BUILD_APPS))
 ifndef LOCAL_DEX_PREOPT
 LOCAL_DEX_PREOPT := true
 endif
 endif
+endif
 
 #################################
 include $(BUILD_SYSTEM)/java.mk