ikiwiki 1.45 doesn't work properly for perl installs not in the system path.

ie:

~/tools/perl-5.8.8/perl Makefile.PL
make

fails, as the 'make' command attempts to use the perl install in PATH, rather than the one ikiwiki is being installed for.

The installed bin/ikiwiki file also refers to /usr/bin/perl rather than the perl it is being installed for.

> I will acdept sufficiently nonintrusive patches to make ikiwiki work better on strange systems like
> yours, but do not plan to work on it myself, since I do not use systems
> where /usr/bin/perl is not a sane default. --[[Joey]]

> > I've implemented a change that should fix this.  For what it's worth this is a
> > life saver on shared hosting where building your own perl is super effective.
> > --frioux ([code here](https://github.com/frioux/ikiwiki/tree/use-env-perl))

[[wishlist]]
