diff --git a/reactos/drivers/input/mouclass/makefile b/reactos/drivers/input/mouclass/makefile
index 766c1cd5a80..531ca0f91b7 100644
--- a/reactos/drivers/input/mouclass/makefile
+++ b/reactos/drivers/input/mouclass/makefile
@@ -6,7 +6,7 @@ TARGET_TYPE = driver
 
 TARGET_NAME = mouclass
 
-TARGET_CFLAGS = -Wall -Werror
+TARGET_CFLAGS = -D__USE_32API -Wall -Werror
 
 TARGET_OBJECTS = $(TARGET_NAME).o