diff --git a/lib/make/msxbuild.mk b/lib/make/msxbuild.mk
index 241de48..b2734a3 100644
--- a/lib/make/msxbuild.mk
+++ b/lib/make/msxbuild.mk
@@ -28,8 +28,8 @@ include $(MB__BASEPATH)/lib/make/mb_tool.mk
 include $(MB__BASEPATH)/lib/make/mb_proj.mk
 include $(MB__BASEPATH)/lib/make/i18n/mb_i18n.mk
 ifneq ("$(MB_I18N)", "off")
-$(if $(wildcard $(MB__BASEPATH)/lib/make/i18n/mb_i18n_$(MB_I18N).mk),,$(error Unsupported i18n language code: $(MB_I18N)))
-include $(MB__BASEPATH)/lib/make/i18n/mb_i18n_$(MB_I18N).mk
+$(if $(MB_I18N),$(if $(wildcard $(MB__BASEPATH)/lib/make/i18n/mb_i18n_$(MB_I18N).mk),,$(error Unsupported i18n language code: $(MB_I18N))))
+$(if $(MB_I18N),$(eval include $(MB__BASEPATH)/lib/make/i18n/mb_i18n_$(MB_I18N).mk))
 endif