Implement national body comment GB9: remove std::gets

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192538 91177308-0d34-0410-b5e6-96231b3b80d8
LWG issue 2143: ios_base::xalloc should be thread-safe

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192539 91177308-0d34-0410-b5e6-96231b3b80d8
LWG Issue 2097: packaged_task constructors should be constrained

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192544 91177308-0d34-0410-b5e6-96231b3b80d8
LWG Issue 2087: iostream_category() and noexcept

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192545 91177308-0d34-0410-b5e6-96231b3b80d8
Updated status of issues and features

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192546 91177308-0d34-0410-b5e6-96231b3b80d8
Patch from GM to make more implicit bools explicit since we can't stop MSVC warning about this in headers and to warn is the MSVC default. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192548 91177308-0d34-0410-b5e6-96231b3b80d8