Changed the way that ld65 handles bad offset/start segment attributes, and reports memory area overflows.

1. Offset/start attributes within a memory area are ignored after an overflow.
2. If a previous segment ends past an offset/start address, then that address is not used.
3. Short map files were generated for memory overflows; now, they are generated for bad offset/start addresses, too.

src/ld65/main.c

@@ -819,8 +819,8 @@ int main (int argc, char* argv [])
         if (MapFileName) {
             CreateMapFile (SHORT_MAPFILE);
         }
-        Error ("Cannot generate output due to memory area overflow%s",
-               (MemoryAreaOverflows > 1)? "s" : "");
+        Error ("Cannot generate most of the files due to memory area overflow%c",
+               (MemoryAreaOverflows > 1) ? 's' : ' ');
     }
 
     /* Create the output file */