Leafnode uses PCRE.  I will always try to build with the latest
installed version.  There is a version of PCRE included in the source,
so if you don't have a development package installed the build should
still work, but Leafnode will not be statically linked against the
system PCRE.  PCRE must be version 2 (or possibly later), not version 1.

The package uses debhelper.  Note that while it conforms to FHS with old
versions, it should also handle newer, more correct versions properly
too.