[Bug-tar] Short option name for --use-compress-program

[Antonio Diaz Diaz]

Hello,

I was going to send a patch adding support for lzip files to tar but, 
given that lzop and maybe other compression programs are already waiting 
for such support and also that we are already scrapping the bottom of 
the barrel regarding short option names, instead I propose to assign a 
short name to the option --use-compress-program.

I think this is a neat way of solving the recurrent problem of adding 
support for new compression formats.


Best regards,
Antonio.