diff --git a/reactos/drivers/bus/isapnp/isapnp.h b/reactos/drivers/bus/isapnp/isapnp.h
index 2844fd15da5..bc34c0e89f4 100644
--- a/reactos/drivers/bus/isapnp/isapnp.h
+++ b/reactos/drivers/bus/isapnp/isapnp.h
@@ -5,6 +5,8 @@
 extern "C" {
 #endif
 
+#define IO_RESOURCE_REQUIRED  0x00  //ROS Extension
+ 
 #define ISAPNP_ADDRESS_PORT   0x0279    // ADDRESS (W)
 #define ISAPNP_WRITE_PORT     0x0A79    // WRITE_DATA (W)
 #define ISAPNP_MIN_READ_PORT  0x0203    // READ_DATA (R)
diff --git a/reactos/drivers/bus/isapnp/makefile b/reactos/drivers/bus/isapnp/makefile
index cd3b5cf9551..bc656b7bdd0 100644
--- a/reactos/drivers/bus/isapnp/makefile
+++ b/reactos/drivers/bus/isapnp/makefile
@@ -8,7 +8,7 @@ TARGET_NAME = isapnp
 
 TARGET_OBJECTS = isapnp.o
 
-TARGET_CFLAGS = -Werror -Wall
+TARGET_CFLAGS = -D__USE_W32API -Werror -Wall
 
 include $(PATH_TO_TOP)/rules.mak