Bug#737843: manipulate unzip behavior

[Osamu Aoki]

control: retitle -1 optional setting of unpack/repack command options

Hi,

I do not think we should change the current default uscan behavior for
unzip to keep other programs happy (other than javaxmail).

At the same time, uscan should be flexible enough to accomodate needs
raised by this bug https://bugs.debian.org/737843

I could easily add unzip option string adding options to watch file.

But that is not generic enough solution.

Allowing watch file to set specific environment variable as persistent
option in the similar way as user-agent may be better idea.  If we had
this, we could do without pasv/active too.  (I know its too late to drop
pasv.)

...

After a good night sleep, I am not sure about security of allowing to
set random environment variables with random values,  PATH, TMP for
example.

So what out there to worry.

 * unzip: UNZIP
 * gzip/gunzip: GZIP
 * xz/unxz: XZ_OPT
 * bzip2/bunzip2 seems to have no equivalent
 * xpi-repack seems to have no equivalent (but not much needs)

It looks like environment variable setting may not address all the
cases.

For compression, we are using default mode only.  So adding following
persistent option may be good idea to solve this original bug issues and
other cases.  Then we can use -v etc for all these commands.

 * opt_compress
 * opt_uncompress

Osamu