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

Clang's 3.5 integrated assembler now handles these files correctly (it
has support for the .codeXX directives). However, it is desirable, for
a time, to allow kernels to be built with clang 3.4. Historically, it
has been advantageous to allow stable X-1 to build kernels the old
way (so long as the impact of doing so is small), and this restores
that ability.

Also, centralize the addition of ${ASM_CFLAGS.${.IMPSRC}}, place it in
kern.mk rather than kern.pre.mk so that all modules can benefit, and
give the same treatment to CFLAGS in kern.mk as well.

Remove the clang -no-integrated-as workaround for smapi_bios.S, as clang
3.5.0 now supports the assembly just fine.

Re-enable -Werror for these modules. It is already enabled for the same
files when built as part of a kernel.

Define several extra macros in bsd.sys.mk and sys/conf/kern.pre.mk, to
get rid of testing explicitly for clang (using ${CC:T:Mclang}) in
individual Makefiles.

Instead, use the following extra macros, for use with clang:
- NO_WERROR.clang (disables -Werror)
- NO_WCAST_ALIGN.clang (disables -Wcast-align)
- NO_WFORMAT.clang (disables -Wformat and friends)
- CLANG_NO_IAS (disables integrated assembler)
- CLANG_OPT_SMALL (adds flags for extra small size optimizations)

As a side effect, this enables setting CC/CXX/CPP in src.conf instead of
make.conf! For clang, use the following:

CC=clang
CXX=clang++
CPP=clang-cpp

MFC after: 2 weeks

Upgrade our copy of llvm/clang to r126079, from upstream's trunk.

This contains many improvements, primarily better C++ support, an
integrated assembler for x86 and support for -pg.

Add WERRROR= to work around the warnings

Add module infrastructure for 'vpd' and 'smbios' and move 'smbios'
to new home.