widl: res50 is number of impinfos. Fix its usage.
diff --git a/tools/widl/typelib_struct.h b/tools/widl/typelib_struct.h
index 83a326b..961105c 100644
--- a/tools/widl/typelib_struct.h
+++ b/tools/widl/typelib_struct.h
@@ -76,7 +76,7 @@
         INT   res44;            /* unknown always: 0x20 (guid hash size?) */
         INT   res48;            /* unknown always: 0x80 (name hash size?) */
         INT   dispatchpos;      /* HREFTYPE to IDispatch, or -1 if no IDispatch */
-/*0x50*/INT   res50;            /* is zero becomes one when an interface is derived */
+/*0x50*/INT   nimpinfos;        /* number of impinfos */
 } MSFT_Header;
 
 /* segments in the type lib file have a structure like this: */