- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Bump .Dd date.

Forgotten by: delphij

Implement the no_user_check option to pam_krb5.

This option is available in the Linux implementation of pam_krb5
and allows to authorize a user not known to the local system.

Ccache is not used as we don't have a secure uid/gid for the cache file.

Usable for authentication of external kerberos users (e.g Active Directory)
via PAM from applications like Cyrus saslauthd, PHP or perl.

PR: bin/146186
Submitted by: myself
Approved by: deplhij (mentor)
MFC after: 2 weeks

Spelling police: sucessful -> successful.

Document the no_warn option.

mdoc(7) police: -xwidth has been fold into -width.

mdoc(7) police: fixed formatting.

Convert to mdoc(7).

Bring in a few useful PAM modules.

pam_krb5 is a Kerberos 5 (Heimdal) authentication module.

pam_nologin checks for /etc/nologin and does the "usual stuff"
if it is found, otherwise it silently succeeds.

pam_rootok silently succeeds if the user is root, otherwise
it fails.

pam_wheel silently succeeds if the user is a member of group
"wheel" (or another nominated group), and fails
otherwise.

There is an issue with kerberosIV and kerberos5 - if both are
being built, then static linking fails with duplicate symbols.
This will take a bit of work to sort out in the kerberii.