tree 63069aa05dd9906122014ada20c104c8fed30912
parent 159b4608682e31025fcb8bf995a7bbb858635b55
author Eric Fiselier <eric@efcs.ca> 1476254711 +0000
committer Eric Fiselier <eric@efcs.ca> 1476254711 +0000

Add <optional> header.

This patch is largely thanks to Casey Carter @ Microsoft. He did the initial
work of porting our experimental implementation and tests over to namespace
std.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283977 91177308-0d34-0410-b5e6-96231b3b80d8