Fixed a watcom warning

git-svn-id: svn://svn.cc65.org/cc65/trunk@2823 b7a2c559-68d2-44c3-8de9-860c34a00d81

src/ld65/exports.c

@@ -687,6 +687,8 @@ static char GetAddrSizeCode (unsigned char AddrSize)
         case ADDR_SIZE_LONG:    return 'L';
         default:
             Internal ("Invalid address size: %u", AddrSize);
+	    /* NOTREACHED */
+	    return '-';
     }
 }