Index: VirtualBox-5.1.2/src/VBox/Main/webservice/Makefile.kmk
===================================================================
--- VirtualBox-5.1.2.orig/src/VBox/Main/webservice/Makefile.kmk
+++ VirtualBox-5.1.2/src/VBox/Main/webservice/Makefile.kmk
@@ -707,7 +707,7 @@ $(VBOXWEB_OUT_DIR)/gsoap_generate_all_ts
 : $(VBOXWEB_GSOAPH_FROM_GSOAP) $(VBOXWEB_GSOAPH_FROM_XSLT) $(VBOX_NSMAP) $(RECOMPILE_ON_MAKEFILE_CURRENT) | $$(dir $$@)
 	$(call MSG_GENERATE,,lots of files,$(GSOAPH_RELEVANT))
 	$(RM) -f $@
-	$(REDIRECT) -C $(VBOXWEB_OUT_DIR) -- $(VBOX_SOAPCPP2) $(VBOXWEB_SOAPCPP2_SKIP_FILES) -L -2 -w -I$(VBOX_PATH_GSOAP_IMPORT) $(GSOAPH_RELEVANT)
+	$(REDIRECT) -C $(VBOXWEB_OUT_DIR) -- $(VBOX_SOAPCPP2) $(VBOXWEB_SOAPCPP2_SKIP_FILES) -z1 -L -2 -w -I$(VBOX_PATH_GSOAP_IMPORT) $(GSOAPH_RELEVANT)
 	$(APPEND) $@ done
 
 # Copy the generated headers and stuff.  This was split into a separate rule