cal: in man page improve grammar and wording of the reformation limitation

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>
unshare: Add possibility to add mapping into root user in user namespace

This makes it very convenient to use make use of privileged actions
on CONFIG_USER_NS enabled kernels, without having to manually tinker
with uid_map and gid_map to obtain required credentials (as those
given upon unshare() vanish with call to execve() and lot of userspace
checks for euid==0 anyway).

Usage example:

$ unshare --uts
unshare: unshare failed: Operation not permitted

$ unshare --user --uts
[nfsnobody@odvarok ~]$ hostname swag
hostname: you must be root to change the host name

$ unshare -r --uts
[root@odvarok util-linux]# hostname swag
[root@odvarok util-linux]#

[kzak@redhat.com: - move code to map_id()
                  - use all-io.h
                  - add paths to pathnames.h]

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Karel Zak <kzak@redhat.com>
uuidd: use pkg-config to find systemd-deamon support

[kzak@redhat.com: - remove USE_SOCKET_ACTIVATION and use
                    HAVE_* as we use for another libs]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Karel Zak <kzak@redhat.com>
dmesg: fix --raw zero timestamp for kmsg

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1049438
Signed-off-by: Karel Zak <kzak@redhat.com>