- 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

head -n doesn't take negative arguments on FreeBSD, so instead use sed '$d'
to remove the last line of a file.

Bring back part of r249367 by adding DTrace's temporal option, which allows
users to guarantee that the output of DTrace scripts will be time-ordered.
This option is enabled by adding the line

#pragma D option temporal

to the beginning of a script, or by adding '-x temporal' to the arguments of
dtrace(1).

This change fixes a bug in the original port of the temporal option. This
bug was causing some assertions to fail, so they had been disabled; in this
revision the assertions are working properly and are enabled.

The DTrace version number has been bumped from 1.9.0 to 1.9.1 to reflect
the language change that's being introduced.

This change corresponds to part of illumos-gate commit e5803b76927480:
3021 option for time-ordered output from dtrace(1M)

Reviewed by: pfg
Obtained from: illumos
MFC after: 1 month

Update vendor/illumos to illumos-gate 13758:23432da34147 (dtrace changes)

References:
https://www.illumos.org/issues/3021
https://www.illumos.org/issues/3022
https://www.illumos.org/issues/3023
https://www.illumos.org/issues/3024
https://www.illumos.org/issues/3025
https://www.illumos.org/issues/3026

Obtained from: ssh://anonhg@hg.illumos.org/illumos-gate