Add phony target dist_libraries

that is only used to put your library into the dist dir when doing a full build.

Change-Id: I11e9dc15237086843ea4a00736c81ffc680ca12e
diff --git a/core/main.mk b/core/main.mk
index 32d67e9..0b4ca38 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -689,6 +689,9 @@
 	$(INSTALLED_USERDATAIMAGE_TARGET) \
 	$(INSTALLED_FILES_FILE)
 
+# dist_libraries only for putting your library into the dist directory with a full build.
+.PHONY: dist_libraries
+
 ifneq ($(TARGET_BUILD_APPS),)
   # If this build is just for apps, only build apps and not the full system by default.
 
@@ -736,7 +739,7 @@
   endif
 
 # Building a full system-- the default is to build droidcore
-droid: droidcore
+droid: droidcore dist_libraries
 
 endif # TARGET_BUILD_APPS