Hi Hilmar,
thanks for that.
I presume you're referring to the GG_DEBIAN_BUILD variable in Makefile, which is used only to guard against including files (or to guard against specific actions) for Debian. It's not used to include anything specific for Debian or to do anything specific for it. It accounts for differences between Debian and other distros (RPM based, such as Fedora or OpenSUSE, or Arch Linux), which need additional files and/or actions. Those additional tasks are currently 1) installing LICENSE file 2) man pages, 3) as well as .dbg files produced by objcopy to make a debug build for Arch package. Those tasks are done for Debian through debian/* files and/or automatically by the build process, so they are excluded from being done through Makefile.
Best,
Sergio