Installing ikiwiki on a shared-hosting server, there may be no access to
install prerequisite Perl modules in the systemwide locations. They may
have to be installed under the home directory, such as by using local::lib
(which is how the cPanel Perl-module installer works, on systems that use it).

For that to work, the local::lib-defined value for PERL5LIB must be in
the environment when Perl starts up. The former way %config{ENV} was handled
was too late, depending on the Perl code to unpack it from the storable and
put it into the environment.

Easy solution is to build the wrapper to repopulate the environment based on
%config{ENV} before ever exec'ing Perl (and then remove it from the storable
as there is nothing more that the Perl code will need to do with it).
More cautious escaping of environment values.

Tightened the escaping per this review comment:
http://source.ikiwiki.branchable.com/?p=source.git;a=commitdiff;h=f35fc6a603b5473ce2c07bb0236e28e57f718315

(I didn't introduce a $tmp, as $val was local to that block already, and each
hex encoding is in its own C string literal to avoid consuming subsequent
chars that are valid hex digits.)
Merge remote-tracking branch 'jcflack/early-env'
write changelog, close bug