commit 3a4b49e283e999a464e3d81ab4907570a1d10944
author Eric Fiselier <eric@efcs.ca> Tue Jun 25 22:13:39 2019 +0000
committer Eric Fiselier <eric@efcs.ca> Tue Jun 25 22:13:39 2019 +0000
tree 7c94517f399db799fb7f35de2ca24164b4fd6a6b
parent 8b2d46d8a21f9393139dddf182065eb732441bc0

Change the ABI version and ABI namespace to be `_LIBCPP_VERSION`
when _LIBCPP_ABI_UNSTABLE is defined.

User defined _LIBCPP_ABI_NAMESPACE will still be respected,
but the default version namespace in unstable mode will be the libc++ version
(Currently '__9000').

Previously  `_LIBCPP_ABI_VERSION` and `_LIBCPP_ABI_NAMESPACE` were
`1` and `__1` respectively, whuch conflicted with the stable ABI

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@364354 91177308-0d34-0410-b5e6-96231b3b80d8