- 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

Upgrade our copy of llvm/clang to 3.3 release.

Release notes are still in the works, these will follow soon.

MFC after: 1 month

Pull in r183033 and r183036 from LLVM trunk:

Add support for optimized (non-generic) atomic libcalls.

For integer types of sizes 1, 2, 4 and 8, libcompiler-rt (and libgcc)
provide atomic functions that pass parameters by value and return
results directly.

libgcc and libcompiler-rt only provide optimized libcalls for
__atomic_fetch_*, as generic libcalls on non-integer types would make
little sense. This means that we can finally make __atomic_fetch_*
work
on architectures for which we don't provide these operations as
builtins
(e.g. ARM).

This should fix the dreaded "cannot compile this atomic library call
yet" error that would pop up once every while.

This should make it possible for me to get C11 atomics working on all of
our platforms.

Upgrade our copy of llvm/clang to trunk r178860, in preparation of the
upcoming 3.3 release (branching and freezing expected in a few weeks).

Preliminary release notes can be found at the usual location:
<http://llvm.org/docs/ReleaseNotes.html>

An MFC is planned once the actual 3.3 release is finished.

Vendor import of clang trunk r178860:
http://llvm.org/svn/llvm-project/cfe/trunk@178860