Windows: Default the DDK build to use _cdecl

The Windows DDK defaults to __stdcall which isn't what we want.

windows/ddk_build/hidapi.def

@@ -1,17 +1 @@
 LIBRARY   hidapi
-EXPORTS
-   hid_open    @1
-   hid_write   @2
-   hid_read    @3
-   hid_close   @4
-   hid_get_product_string @5
-   hid_get_manufacturer_string @6
-   hid_get_serial_number_string @7
-   hid_get_indexed_string @8
-   hid_error @9
-   hid_set_nonblocking @10
-   hid_enumerate @11
-   hid_open_path @12
-   hid_send_feature_report @13
-   hid_get_feature_report @14
-   

windows/ddk_build/sources

@@ -3,6 +3,8 @@ TARGETTYPE=DYNLINK
 UMTYPE=console
 UMENTRY=main
 
+386_STDCALL=0
+
 MSC_WARNING_LEVEL=/W3 /WX
 
 TARGETLIBS=$(SDK_LIB_PATH)\hid.lib \