configure should check for more things

[andersk@mit.edu]

$ ./configure
…
Note (probably harmless): No library found for -lperl

No, that’s not exactly harmless. configure should enforce its check for Perl headers.

$ make
…
cd blib; zip -q ../Jabber.par -r arch lib
/bin/sh: zip: command not found

configure should check for zip.

t/00-core-tests....ok
t/completion.......Base class package "Class::Accessor::Fast" is empty.
    (Perhaps you need to 'use' the module which defines that package first.)
 at t/../perl/lib/BarnOwl/Completion/Context.pm line 41

configure should check for Class::Accessor::Fast.