duplicates in the module list break build

They might occur in extensions when crosscompiling, because both
harfbuzz and lcms2 are listed twice.

Change-Id: I6d6eff19043d33160b825f47988e46798da7857a

solenv/gbuild/Module.mk

@@ -280,7 +280,8 @@ $(foreach target,$(2),$(call gb_Module_add_subsequentcheck_target,$(1),$(target)
 endef
 
 define gb_Module_add_moduledirs
-$(foreach target,$(2),$(call gb_Module_add_moduledir,$(1),$(target)))
+$(foreach target,$(sort $(2)),$(call gb_Module_add_moduledir,$(1),$(target)))
+
 endef
 
 define gb_Module_make_global_targets