Fixes problems when lzx tries to handle 0 lenght archives.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                 1194    1716  69.6% -lh5- a0d4 Mar 24  1996 no0
[generic]                  596    1254  47.5% -lh5- d135 Mar 24  1996 no0.c
[generic]                  301     508  59.3% -lh5- d8cd Mar 24  1996 no0.doc
[generic]                   79     111  71.2% -lh5- ea4b Mar 24  1996 scoptions
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         4 files    2170    3589  60.5%            Mar 29  1996