diff --git a/lib/Makefile.m32 b/lib/Makefile.m32
index 76171cb9b..8c0e5a467 100644
--- a/lib/Makefile.m32
+++ b/lib/Makefile.m32
@@ -138,9 +138,8 @@ ifdef IDN
   DLL_LIBS += -L$(LIBIDN_PATH)/lib -lidn
 else
 ifdef WINIDN
-  INCLUDES += -I"$(WINIDN_PATH)/include"
-  CFLAGS += -DHAVE_NORMALIZATION_H
   CFLAGS += -DUSE_WIN32_IDN
+  CFLAGS += -DWANT_IDN_PROTOTYPES
   DLL_LIBS += -L"$(WINIDN_PATH)" -lnormaliz
 endif
 endif