Clean-up and make the art script usable on target.

Also add a phony target to build what's needed to use it.

Change-Id: I0bca6b0cbe921653de05fec0ae0cbbff63df580e
diff --git a/Android.mk b/Android.mk
index 15e8308..669939b 100644
--- a/Android.mk
+++ b/Android.mk
@@ -355,7 +355,7 @@
 build-art-target: $(ART_TARGET_EXECUTABLES) $(ART_TARGET_GTEST_EXECUTABLES) $(TARGET_CORE_IMG_OUT) $(TARGET_OUT_SHARED_LIBRARIES)/libjavacore.so
 
 ########################################################################
-# "m art-host" for just building the files needed to run the art script
+# "m art-host" for just building the files needed to run the art script on the host.
 .PHONY: art-host
 ifeq ($(HOST_PREFER_32_BIT),true)
 art-host:   $(HOST_OUT_EXECUTABLES)/art $(HOST_OUT)/bin/dalvikvm32 $(HOST_OUT)/lib/libart.so $(HOST_OUT)/bin/dex2oat $(HOST_OUT)/bin/patchoat $(HOST_CORE_IMG_OUT) $(HOST_OUT)/lib/libjavacore.so $(HOST_OUT)/bin/dalvikvm
@@ -363,6 +363,11 @@
 art-host:   $(HOST_OUT_EXECUTABLES)/art $(HOST_OUT)/bin/dalvikvm64 $(HOST_OUT)/bin/dalvikvm32 $(HOST_OUT)/lib/libart.so $(HOST_OUT)/bin/dex2oat $(HOST_OUT)/bin/patchoat $(HOST_CORE_IMG_OUT) $(HOST_OUT)/lib/libjavacore.so $(HOST_OUT)/lib64/libjavacore.so $(HOST_OUT)/bin/dalvikvm
 endif
 
+# "m art-target" for just building the files needed to run the art script on the target.
+# Note that the script can run a dalvikvm executable that is not necessarily /system/bin/dalvikvm.
+.PHONY: art-target
+art-target: adb build-art-target art libnativehelper libjavacore
+
 .PHONY: art-host-debug
 art-host-debug:   art-host $(HOST_OUT)/lib/libartd.so $(HOST_OUT)/bin/dex2oatd $(HOST_OUT)/bin/patchoatd