- 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

Add an additional regression tests for other cases to ensure these do not get fixed by accident.

POSIX requires that non-existent or null arguments be treated as if a
zero argument were supplied.

Add a regression test to catch this case as well.

PR: bin/174521
Submitted by: Daniel Shahaf <danielsh@elego.de> (pr)
Submitted by: Mark Johnston <markjdb@gmail.com> (initial patch)
Reviewed by: jilles
Approved by: cperciva (implicit)
MFC after: 3 weeks

printf: Allow multibyte characters for '<char> form, avoid negative codes.

Examples:
LC_ALL=en_US.UTF-8 printf '%d\n' $(printf \'\\303\\244)
LC_ALL=en_US.ISO8859-1 printf '%d\n' $(printf \'\\344)
Both of these should print 228.

Like some other shells, incomplete or invalid multibyte characters yield the
value of the first byte without a warning.

Note that there is no general way to go back from the character code to the
character.

printf: Test that the "--" option terminator works.

Also test \0 in the format string.

Add a few regression tests for printf(1).