libstore so that the Perl bindings can use it as well. It's vital
that the Perl bindings use the configuration file, because otherwise
nix-copy-closure will fail with a ‘database locked’ message if the
value of ‘use-sqlite-wal’ is changed from the default.
bindings to be used in Nix's own Perl scripts.
The only downside is that Perl XS and Automake/libtool don't really
like each other, so building is a bit tricky.