I downloaded
git clone
github.com/LinuxCNC/linuxcnc.git
I believe it gives latest of 2.8 master branch
Then followed the instructions
linuxcnc.org/docs/html/code/building-linuxcnc.html
I had to download many dependency packages manually as somehow it was not being found during install. But I made sure I am installing the same version as its looking for.
I had to build with following option as it was giving some GPL related error
./configure --enable-non-distributable=yes
All test cases ran with 0 errors.
However I still see following when run dpkg-checkbuilddeps command
dpkg-checkbuilddeps: error: Unmet build dependencies: asciidoc (>= 8.5) dblatex (>= 0.2.12) docbook-xsl dvipng w3c-linkchecker xsltproc texlive-lang-french texlive-lang-german texlive-lang-polish texlive-lang-spanish asciidoc-dblatex texlive-xetex