- 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

Fix typo: WRDE_DOOFS -> WRDE_DOOFFS.

Noticed by: Stoned Elipot

Describe WRDE_NOCMD in the same way that we describe the rest of the flags.

Unbreak for the !__XSI_VISIBLE case when another header that defines
size_t has not been included first.

Add "restrict" qualifiers to the prototype for wordexp().

Add the POSIX <wordexp.h> header file.

PR: 13420