Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

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

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Integrate tools/regression/lib/libc/stdio into the FreeBSD test suite
as lib/libc/tests/stdio

- Fix some whitespace
- Convert the testcases to ATF
- Convert "/dev/null" to _PATH_DEVNULL

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

libc/stdio: Fail fdopen() on an execute-only fd.

An execute-only fd (opened with O_EXEC) allows neither read() nor write()
and is therefore incompatible with all stdio modes. Therefore, the [EINVAL]
error applies.

Also adjust the similar check in freopen() with a NULL path, even though
this checks an fd which is already from a FILE.