[Q] Omitting apps from CM Source Build, question.. topic

A few months back i built CM 10 (4.1.2) Wingray from source.
What id like to do now is omit/remove a couple of the apps from the build, like..

Apollo
CM File Manager
CM Wallpapers
Video Editor

I know i can just remove the apps from the ZIP after the build completes, but would to compile and build without the apps.

My question is this..

What files (and where are they) do i need to edit to remove the above mentioned apps from the build process?

any help, would be greatly appreciated.
Thanks