Merge branch 'upstream' into 'debian/sid'

See merge request !3

update upstream

See merge request !2

It seems that the distributions places nologin in different
places (e.g. deb based distribution in /usr/sbin, rpm based and gentoo
in /sbin).  This patch fixes this behaviour searching for nologin in
the PATH environment variable.

Now a variable for the SPOOL_DIR is been allocated.

Now a variable is used for the spool file and the installation process
is less verbose.

As for the PostInstall script, the Uninstall script must be
adapted to the new username (_cado)

The getopt_long descriptors was not correctly terminated.
To avoid a segmentation fault the list should be terminated
by an array composed of 4 NULLs.

PostInstall was refactored to mimick the debian installer.

update upstream

See merge request !1

PostInstall check, removed unused retvalue warnings, config.h patch

CMake conversion