[llvm-branch-commits] [libcxx] release/20.x: [libc++] Avoid including <features.h> on arbitrary platforms (#125587) (PR #127310)

[Louis Dionne via llvm-branch-commits]

ldionne wrote:

@tstellar Can we merge this one? I have another fix I want to cherry-pick which depends on this one.

https://github.com/llvm/llvm-project/pull/127310