more win32 gui fuzzer work

include/extern.h

@@ -175,6 +175,7 @@ E boolean NDECL(status_hilite_menu);
 
 E char NDECL(randomkey);
 E void FDECL(random_response, (char *, int));
+E int NDECL(rnd_extcmd_idx);
 E int NDECL(doconduct);
 E int NDECL(domonability);
 E char FDECL(cmd_from_func, (int NDECL((*))));

include/func_tab.h

@@ -22,6 +22,5 @@ struct ext_func_tab {
 };
 
 extern struct ext_func_tab extcmdlist[];
-extern int extcmdlist_length;
 
 #endif /* FUNC_TAB_H */

win/win32/mhdlg.c

@@ -168,7 +168,7 @@ int
 mswin_ext_cmd_window(int *selection)
 {
     if (iflags.debug_fuzzer) {
-        *selection = rn2(extcmdlist_length + 1) - 1;
+        *selection = rnd_extcmd_idx();
 
         if (*selection != -1)
             return IDOK;