Add a new _LIBCPP_UNUSED define in __config, which can be used to
indicate explicitly unused items, and apply it to the __imp__ field of
__libcpp_refstring.
Somebody who knows about Microsoft C++ and IBM C++ should fill in the
unused attribute syntax appropriate for those compilers, if there is
any.
Differential Revision: http://reviews.llvm.org/D6836
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@228281 91177308-0d34-0410-b5e6-96231b3b80d8
compatibility to libstdc++. Move the implementation into a header for
easier sharing with libc++abi. Merge a number of improvements from that
version. Provide a POD definition for <stdexcept>'s public use to avoid
cast dances. Discussed with Marshall Clow.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@207695 91177308-0d34-0410-b5e6-96231b3b80d8
