Reset literal queue after unknown preprocessor directive

Fix an assertion failure at sc1.c:3702 (litidx==0).

source/compiler/sc2.c

@@ -1594,6 +1594,7 @@ static int command(void)
       error(31);    /* unknown compiler directive */
       ret=CMD_NONE; /* process as normal line */
     }
+    litidx=0;       /* this directive was added to the literal queue - reset it */
   } /* switch */
   return ret;
 }