gbuild: add gb_ExternalProject_use_jars

Change-Id: Idd67548cb5f0e49e539459ed7f2fbd107d37c1b3

languagetool/ExternalProject_languagetool.mk

@@ -13,11 +13,14 @@ $(eval $(call gb_ExternalProject_register_targets,languagetool,\
 	build \
 ))
 
-$(call gb_ExternalProject_get_state_target,languagetool,build) : \
-            $(call gb_Jar_get_target,juh) \
-            $(call gb_Jar_get_target,jurt) \
-            $(call gb_Jar_get_target,ridl) \
-            $(call gb_Jar_get_target,unoil)
+$(eval $(call gb_ExternalProject_use_jars,languagetool,\
+	juh \
+	jurt \
+	ridl \
+	unoil \
+))
+
+$(call gb_ExternalProject_get_state_target,languagetool,build) :
 	cd "$(call gb_UnpackedTarball_get_dir,languagetool)" && \
 	$(ICECREAM_RUN) "$(ANT)" \
 		-q \

solenv/gbuild/ExternalProject.mk

@@ -184,6 +184,15 @@ $(call gb_ExternalProject_get_preparation_target,$(1)) : \
 
 endef
 
+# Make an external project depend on a Jar file
+#
+# gb_ExternalProject_use_jars external jars
+define gb_ExternalProject_use_jars
+$(call gb_ExternalProject_get_preparation_target,$(1)) : \
+	$(foreach jar,$(2),$(call gb_Jar_get_target,$(lib)))
+
+endef
+
 # Run a target command
 #
 # This provides a wrapper that changes to the right directory,