virtualbox-ose-additions - build fails due to env mixup

[Domagoj Smolčić]

virtualbox-ose-additions-5.2.22 and below

If user which su-ed to root, has in it's .shrc file, inclusion of i.e;
. $HOME/_some_file.sh, during build, that file is included from /root/
instead and build fails with:
    .: Can't open /root/_some_file.sh
As /usr/local/bin/kmk reports (kBuild-0.1.9998_11)

WORKAROUND:
    Uncomment inclusion line
  OR
    Log in directly as a root


Domagoj Smolčić