- 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

Add a c++/v1/tr1 include directory containing symlinks to all of the standard
headrs.

Lots of third-party code expects to find C++03 headers under tr1 because that's
where GNU decided to hide them. This should fix ports that expect them there.

MFC after: 1 week

After r253839, which modifies ld's behaviour to not automatically pull
in needed libraries, change libc++.so into a linker script, so it can
automatically pull in libcxxrt.so.

MFC after: 1 week

Fix broken macro checking in the libc++ Makefile, introduced in r241909.
This caused -std=c++0x not to be passed to the build by default.

Pointy hat to: dim
MFC after: 3 days

Allow building libc++ with any custom -std=xxx flag. Note that using
-std=gnu++98 will give a lot of warnings with clang, so please use
-std=c++0x or higher, or use NO_WERROR.

MFC after: 1 week

Add libcxxrt's objects (prefixing them with cxxrt_ to avoid collisions)
to libc++.a and libc++_p.a, to make static linking of C++ executables
with libc++ easier. This is similar to the approach used in libstdc++.

MFC after: 2 weeks

Install libcxxrt's C++ ABI and unwind headers. This is done in libc++'s
Makefile, so these headers go into the same destination directory as
libc++'s own headers, currently /usr/include/c++/v1.

MFC after: 3 days

Tabify libcxxrt and libc++'s Makefiles.

MFC after: 3 days

Make sure libgcc_s is finished building in _startup_libs before
building libcxxrt with high -j levels. The workaround in
libc++/Makefile isn't necessary once that race is solved.

Reviewed by: theravin

Import new versions of libcxxrt and libc++.
Please tests any C++ code you care about with -stdlib=libc++!

Approved by: dim (mentor)

Import libc++ / libcxxrt into base. Not build by default yet (use
MK_LIBCPLUSPLUS=yes to enable). This is a work-in-progress. It works for
me, but is not guaranteed to work for anyone else and may eat your dog.

To build C++ using libc++, add -stdlib=libc++ to your CXX and LD flags.

Bug reports welcome, bug fixes even more welcome...

Approved by: dim (mentor)