[ITA] bzip2-1.0.8 (updated with pkg-config support)

bzip2-1.0.8 does not include support for pkg-config, but all major
linux distributions included it, by providing the script directly to
the package.
See for example the sources of that package for arch linux:

https://gitlab.archlinux.org/archlinux/packaging/packages/bzip2

I did a similar thing, by adding a bzip2.pc.in, which will be used by
the cygport script for generating the bzip2.pc file.
While I was on the topic, I also improved a bit the script, by adding
the information about the license.
I hope that the maintainer of the BZip2 package for CYGWIN will find it useful.

Sincerely,

Carlo Bramini.