Missing dependency on directory

Change-Id: Icaf0f54d3487c8286486d265ebb9790f6b9e0910
Reviewed-on: https://gerrit.libreoffice.org/55419Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

solenv/gbuild/AllLangHelp.mk

@@ -94,7 +94,8 @@ endif
 endef
 
 ifneq ($(ENABLE_HTMLHELP),)
-$(call gb_AllLangHelp_get_helpfiles_target,%):
+$(call gb_AllLangHelp_get_helpfiles_target,%): | \
+        $(dir $(call gb_AllLangHelp_get_helpfiles_target,%)).dir
 	touch $@
 endif