Scripts to build the various debian packages from postgresql source

I would like to build from source, however I would like to integrate
with the scripts included in the ubuntu packages from
https://wiki.postgresql.org/wiki/Apt. Where are the scripts that are
used to build the various relevant packages from presumably these
postgresql sources:

http://www.postgresql.org/download/

For example, I have come up with the following configure parameters,
but it would appear that the ubuntu packages provide source in
different format as the /usr/include/postgresql directory contains
files from the source includes that are presumably shared across
versions of postgresql.

$ver=9.3
$type=main
./configure --prefix=--bindir=/usr/lib/postgresql/$ver/
--datarootdir=/usr/share/postgresql/$ver
--sysconfdir=/etc/postgresql/$ver/$type

--includedir=/usr/include/postgresql/$ver unfortunately the include
dir /usr/include/postgresql/ appears to be comprised of files provided
by various packages

I would prefer to build from a set of scripts instead of attempting to
backwords engineer the build.