-OcamlSources := $(OcamlSources1:$(PROJ_SRC_DIR)/%=$(ObjDir)/%)
-OcamlHeaders := $(OcamlHeaders1:$(PROJ_SRC_DIR)/%=$(ObjDir)/%)
+ifndef OcamlHeaders1
+OcamlHeaders1 := $(sort $(wildcard $(PROJ_SRC_DIR)/*.mli))
+endif
+
+OcamlSources2 := $(filter-out $(ExcludeSources),$(OcamlSources1))
+OcamlHeaders2 := $(filter-out $(ExcludeHeaders),$(OcamlHeaders1))
+
+OcamlSources := $(OcamlSources2:$(PROJ_SRC_DIR)/%=$(ObjDir)/%)
+OcamlHeaders := $(OcamlHeaders2:$(PROJ_SRC_DIR)/%=$(ObjDir)/%)