bug#5475: Archives with filenames with square brackets

[Eli Zaretskii]

> From: Juri Linkov <juri@jurta.org>
> Cc: cyd@stupidchicken.com,  5475@debbugs.gnu.org
> Date: Sun, 31 Jan 2010 12:56:19 +0200
> 
> >> The default value of `archive-zip-extract' can be either "unzip" or
> >> "pkunzip" (depending on the presence of the executable in `exec-path'),
> >> but the function `archive-zip-extract' compares with the value "pkzip".
> >> So the pkzip/pkunzip branch is never executed.
> >>
> >> It seems the intention of the change revno#45347 (2002-05-19) was
> >> to compare with "pkunzip" instead of "pkzip"
> >
> > Right, looks like a bug.
> >
> > Btw, I looked into 7z, and it doesn't have the same problem as unzip.
> > So we probably should only quote with unzip.
> 
> Does the following patch look right?  At least, it fixes a bug, and
> after feature freeze we could add more data structures to defcustom to
> indicate whether the file name needs to be quoted.

Looks okay to me, except that perhaps compare strings
case-insensitively instead of just with `equal'.