For debian, its quite simple. I added at the top of the build-unix.txt that you need to mkdir "obj" in the src folder before running the makefile.
No other modifications are necessary.
Its a two step process really...
Assuming you have your build environment setup already:
apt-get install ntp git build-essential libssl-dev libdb-dev libdb++-dev libboost-all-dev libqrencode-dev
The two steps are:
1. clone the github using "git clone X" where X is my github.
2. cd into /premineplus/src/ folder and run "make -f makefile.unix USE_UPNP=-"
done.
https://litecoin.info/Compiling_the_Litecoin_daemon_from_source_on_Debian has a great guide.
I originally used
https://bitcointalk.org/index.php?topic=460178.msg7150412#msg7150412 because it walks you through setting up a memory swap file (good if you are using a droplet or small vps).
wish windows compiling was so easy -_-
I'll add a link to those instructions you provided in the build docs.