[PATCH] D36713: [libc++] Add a persistent way to disable availability

[Shoaib Meenai via Phabricator via cfe-commits]

smeenai added a comment.

In https://reviews.llvm.org/D36713#841478, @mclow.lists wrote:

> What's the use case here?  What are you trying to accomplish?


The `_LIBCPP_DISABLE_AVAILABILITY` macro already exists, but since it influences headers, it's a lot more useful to have it as a site config option, so that it can be set consistently.

I have an internal codebase where the availability macros cause issues, for complicated reasons that I unfortunately can't go into detail about. Rather than having to add `_LIBCPP_DISABLE_AVAILABILITY` to every single build using the libc++ headers, it would be really nice to be able to do the disabling via the site config. I know that's not a very satisfying explanation, but this seemed like a small and generally useful change, and it's consistent with how we're handling other macros that influence headers.


https://reviews.llvm.org/D36713