How to fake an user existence during packaging
I'm repackaging a software (which has its own installer) for private use under a Debian-based system. That software is already compiled (no source), so I basically run the installer into the DESTDIR tree. I wish to use a Debian package instead of each own installer because I like to have things standardly done -- with files going into /usr instead of /opt/package, etc.
Unfortunately, the installer requires that a system username and groupname is previously created. Now, I know it is a simple matter of doing it "by hand" prior to building (and installing) the Debian package. But I'm wondering if it is possible to instruct debuild to "fake the creation of a user" or "fake user xyz already existing" (while running as root with fakeroot). This concerns the build stage, since it seems that the software does not require that the user exists at runtime.
So basically this ammounts to let the Debian build tools (and tools run within the build) to "believe" that a certain user already exists... Short of running in a chroot environment (such as pbuilder), to avoid having to actually create an user, how can I do this? I understand this is just a matter of creating the user myself as root, but I'd like to make this as automatic as possible.