Merge llvm-project release/16.x llvmorg-16.0.4-0-gae42196bc493

This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-16.0.4-0-gae42196bc493 (aka 16.0.4 release).

PR: 271047
MFC after: 1 month

Merge llvm-project 12.0.0 release

This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-12.0.0-0-gd28af7c654d8, a.k.a. 12.0.0 release.

PR: 255570
MFC after: 6 weeks

Regenerate ReStructuredText based manpages for llvm-project tools:

* bugpoint.1
* clang.1
* llc.1
* lldb.1
* lli.1
* llvm-ar.1
* llvm-as.1
* llvm-bcanalyzer.1
* llvm-cov.1
* llvm-diff.1
* llvm-dis.1
* llvm-dwarfdump.1
* llvm-extract.1
* llvm-link.1
* llvm-mca.1
* llvm-nm.1
* llvm-pdbutil.1
* llvm-profdata.1
* llvm-symbolizer.1
* llvm-tblgen.1
* opt.1

Add newly generated manpages for:

* llvm-addr2line.1 (this is an alias of llvm-symbolizer)
* llvm-cxxfilt.1
* llvm-objcopy.1
* llvm-ranlib.1 (this is an alias of llvm-ar)

Note that llvm-objdump.1 is an exception, as upstream has both a plain
.1 file, and a .rst variant. These will have to be reconciled upstream
first.

MFC after: 3 days

Update llvm tool manpages, and llvm-mca.1.

Regenerate llvm tools manpages, and add one for llvm-pbdutil.

Regenerate llvm and clang manpages.

Update Makefiles and other build glue for llvm/clang 3.7.0, as of trunk
r238337.

Regenerated llvm/clang manpages.

Regenerate the manpages for the additional llvm/clang tools. This
contains only very minor updates.

Upgrade our copy of llvm/clang to 3.4 release. This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3. The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC after: 1 month

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.

Upgrade our copy of llvm/clang to trunk r162107. With thanks to
Benjamin Kramer and Joerg Sonnenberger for their input and fixes.

Upgrade our copy of llvm/clang to trunk r154661, in preparation of the
upcoming 3.1 release (expected in a few weeks). Preliminary release
notes can be found at: <http://llvm.org/docs/ReleaseNotes.html>

MFC after: 2 weeks

Add a WITH_CLANG_EXTRAS option for src.conf(5), disabled by default,
that builds the following additional llvm/clang tools:

- bugpoint
- llc
- lli
- llvm-ar
- llvm-as
- llvm-bcanalyzer
- llvm-diff
- llvm-dis
- llvm-extract
- llvm-ld
- llvm-link
- llvm-mc
- llvm-nm
- llvm-objdump
- llvm-prof
- llvm-ranlib
- llvm-rtdyld
- llvm-stub
- macho-dump
- opt

These tools are mainly useful for people that want to manipulate llvm
bitcode (.bc) and llvm assembly language (.ll) files, or want to tinker
with llvm and clang themselves.

MFC after: 2 weeks

Regenerate ReStructuredText based manpages for llvm-project tools:

* bugpoint.1
* clang.1
* llc.1
* lldb.1
* lli.1
* llvm-ar.1
* llvm-as.1
* llvm-bcanalyzer.1
* llvm-cov.1
* llvm-diff.1
* llvm-dis.1
* llvm-dwarfdump.1
* llvm-extract.1
* llvm-link.1
* llvm-mca.1
* llvm-nm.1
* llvm-pdbutil.1
* llvm-profdata.1
* llvm-symbolizer.1
* llvm-tblgen.1
* opt.1

Add newly generated manpages for:

* llvm-addr2line.1 (this is an alias of llvm-symbolizer)
* llvm-cxxfilt.1
* llvm-objcopy.1
* llvm-ranlib.1 (this is an alias of llvm-ar)

Note that llvm-objdump.1 is an exception, as upstream has both a plain
.1 file, and a .rst variant. These will have to be reconciled upstream
first.

MFC after: 3 days

Update llvm tool manpages, and llvm-mca.1.

Regenerate llvm tools manpages, and add one for llvm-pbdutil.

Regenerate llvm and clang manpages.

Update Makefiles and other build glue for llvm/clang 3.7.0, as of trunk
r238337.

Regenerated llvm/clang manpages.

Regenerate the manpages for the additional llvm/clang tools. This
contains only very minor updates.