[PATCH] D55791: [libcxx] Simplify conditional definition of _LIBCPP_HAS_NO_ALIGNED_ALLOCATION

[Louis Dionne via Phabricator]

ldionne added a comment.

In D55791#1348291 <https://reviews.llvm.org/D55791#1348291>, @mclow.lists wrote:

> In general, we *do* protect against user-defined defines.  
>  This, and defining stuff as negative (`_LIBCPP_HAS_NO_XXX`) lets users disable parts of the libc++ functionality by defining the macros.
>
> So I think we should leave this "as is"


The problem I have with this is that we're hence implicitly supporting this use case, which means we should make sure we don't break it, we should add a tester with this configuration, and we should document that this macro can be used to alter the behaviour of the library. Either we should do this if we have a reason to, or we should remove this accidental API by not checking whether the user defines the macro. Does this make sense?


Repository:
  rCXX libc++

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https://reviews.llvm.org/D55791