- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

Use appropriate error codes for each facility instead of just PAM_AUTH_ERR.

Noticed by: pjd

Major cleanup:

- add __unused where appropriate
- PAM_RETURN -> return since OpenPAM already logs the return value.
- make PAM_LOG use openpam_log()
- make PAM_VERBOSE_ERROR use openpam_get_option() and check flags
for PAM_SILENT
- remove dummy functions since OpenPAM handles missing service
functions
- fix various warnings

Sponsored by: DARPA, NAI Labs

Three times lucky: <stddef.h>, not <sys/param.h>

Oops, the correct header to include for NULL is <sys/param.h>.

#include <sys/types.h> for NULL (hidden by Linux-PAM header pollution)

Sponsored by: DARPA, NAI Labs

#include cleanup.

Sponsored by: DARPA, NAI Labs

WARNS=4 fixes. Protect with NO_WERROR for the modules that have
warnings that are hard to fix or that I've been asked to leave alone.

Add __FBSDID()s to libpam

Verbosely report errors to the user (overridable), and make sure
that the correct failure mode is reported.

Clean up (and in some cases write) the PAM mudules, using
o The new options-processing API
o The new DEBUG-logging API

Add man(1) pages for ALL modules. MDOC-Police welcome
to check this.

Audit, clean up while I'm here.