Ubuntu – Configuration and compilation settings used for Ubuntu packages

I want to be able to recreate specific packages by compiling the source code of the package. To compile the source code one has to run the configuration process, followed by the compilation process. I know how to do it, just not what specifics Ubuntu is supplying.

Packages could be Empathy, Banshee or specific libraries for that matter. I can compile them just fine using the (general) information provided at each project site. In a lot of cases I do, however, end up with a build which is just not quite the same as the original one. Slightly different menu options, some functionality functioning differently or not at all, etc.

Is there any source where the configuration and compilation options can be found which are used for the packages included in Ubuntu? Possible also Ubuntu or Debian specific patches.