make sure libpq is in place before it is used

Change-Id: I799a149b319bb6a3168117810084496f8b6d6fbb

RepositoryExternal.mk

@@ -1772,6 +1772,10 @@ else # !SYSTEM_POSTGRESQL
 
 define gb_LinkTarget__use_postgresql
 
+$(call gb_LinkTarget_use_packages,$(1),\
+	postgresql \
+)
+
 $(call gb_LinkTarget_set_include,$(1),\
 	-I$(OUTDIR)/inc/postgresql \
 	$$(INCLUDE) \

connectivity/Library_postgresql-sdbc-impl.mk

@@ -64,10 +64,6 @@ $(eval $(call gb_Library_use_externals,postgresql-sdbc-impl,\
 ifneq ($(SYSTEM_POSTGRESQL),YES)
 ifneq ($(GUI)$(COM),WNTMSC)
 
-$(eval $(call gb_Library_use_external_package,postgresql-sdbc-impl,\
-	postgresql \
-))
-
 -include $(OUTDIR)/inc/postgresql/libpq-flags.mk
 
 $(eval $(call gb_Library_add_libs,postgresql-sdbc-impl,\