Import libc++ 3.4 release. This contains a lot of bugfixes, and some
preliminary support for C++1y.
MFC r261604:
HEAD is not buildable for the past day. Commit a 'quick fix' in order to permit
buildworld to complete.
Reviewed by: theraven
MFC r261608:
Apply a cleaner solution for the sign warnings that can occur when
compiling libc++'s <locale> header with -Wsystem-headers on.
This has also been submitted upstream.
Reported by: asomers
MFC r261801:
An ABI incompatibility crept into the libc++ 3.4 import in r261283. It
was caused by upstream libc++ commit r194536, which aimed to make the
headers more standards-compliant, by making std::pair's copy constructor
trivial. Unfortunately, this could cause certain C++ applications using
shared libraries built against the previous version of libc++ to crash.
Fix the ABI incompatibility by making std::pair's copy constructor
non-trivial again.
Please note: Any C++ applications or shared libraries built with libc++
between r261283 and this revision should be recompiled.
Reported by: stefanf