Makefile will now only test for Linux systems, a work around in the
makefile due to some silly redefine restrictions.
uptime and w now won't error due to being one user logged in, thanks to
Sami for the patch
kill processes by pid test commented out due to false negatives
pwdx process 1 check also commented out due to false negatives
procps works well on Linux, on other arches there are some strange
differences due to their emulation of procfs which is not 100%
Disabling checks for non-linux until that can be sorted out.
