-PRINTABLE_LUFA_BUILD_MODULES = $(if $(strip $(SORTED_LUFA_BUILD_MODULES)), $(SORTED_LUFA_BUILD_MODULES), (None))
-PRINTABLE_LUFA_BUILD_TARGETS = $(if $(strip $(SORTED_LUFA_BUILD_TARGETS)), $(SORTED_LUFA_BUILD_TARGETS), (None))
-PRINTABLE_LUFA_MANDATORY_VARS = $(if $(strip $(SORTED_LUFA_MANDATORY_VARS)), $(SORTED_LUFA_MANDATORY_VARS), (None))
-PRINTABLE_LUFA_OPTIONAL_VARS = $(if $(strip $(SORTED_LUFA_OPTIONAL_VARS)), $(SORTED_LUFA_OPTIONAL_VARS), (None))
-PRINTABLE_LUFA_PROVIDED_VARS = $(if $(strip $(SORTED_LUFA_PROVIDED_VARS)), $(SORTED_LUFA_PROVIDED_VARS), (None))
-PRINTABLE_LUFA_PROVIDED_MACROS = $(if $(strip $(SORTED_LUFA_PROVIDED_MACROS)), $(SORTED_LUFA_PROVIDED_MACROS), (None))
+PRINTABLE_LUFA_BUILD_MODULES = $(call CONVERT_TO_PRINTABLE, $(SORTED_LUFA_BUILD_MODULES))
+PRINTABLE_LUFA_BUILD_TARGETS = $(call CONVERT_TO_PRINTABLE, $(SORTED_LUFA_BUILD_TARGETS))
+PRINTABLE_LUFA_MANDATORY_VARS = $(call CONVERT_TO_PRINTABLE, $(SORTED_LUFA_MANDATORY_VARS))
+PRINTABLE_LUFA_OPTIONAL_VARS = $(call CONVERT_TO_PRINTABLE, $(SORTED_LUFA_OPTIONAL_VARS))
+PRINTABLE_LUFA_PROVIDED_VARS = $(call CONVERT_TO_PRINTABLE, $(SORTED_LUFA_PROVIDED_VARS))
+PRINTABLE_LUFA_PROVIDED_MACROS = $(call CONVERT_TO_PRINTABLE, $(SORTED_LUFA_PROVIDED_MACROS))