Fix creating _dist_<goal> targets under !dist

I had initially thought that we would have created the rule when marking
it as PHONY, but that's apparently not the case.

Bug: 117463001
Test: m test-art-host-gtest
Change-Id: I5e397423dfb138725db0e3e07b2630f8e872bb12

Author: danw

Diff for: packaging/distdir.mk

@@ -24,7 +24,8 @@ $(foreach pair,$(DIST_GOAL_OUTPUT_PAIRS), \
   $(eval output := $(call word-colon,2,$(pair))) \
   $(eval .PHONY: _dist_$$(goal)) \
   $(if $(call streq,$(DIST),true),\
-    $(eval _dist_$$(goal): $$(DIST_DIR)/$$(output))))
+    $(eval _dist_$$(goal): $$(DIST_DIR)/$$(output)), \
+    $(eval _dist_$$(goal):)))
 
 define copy-one-dist-file
 $(2): $(1)