SCP: Extend SHOW processing for default (unspecified) device to also handle global show modifiers, thus making SHOW RADIX display the radix for the default device (usually CPU).

scp.c

@@ -4036,9 +4036,13 @@ else {
                 }
             }
         }
-    if (!dptr)
+    if (!dptr) {
+        if ((shptr = find_shtab (show_dev_tab, gbuf)))  /* global match? */
+            return shptr->action (ofile, sim_dflt_dev, uptr, shptr->arg, cptr);
+        else
             return SCPE_NXDEV;                          /* no match */
         }
+    }
 
 if (*cptr == 0) {                                       /* now eol? */
     return (lvl == MTAB_VDV)?