[libcxx-commits] [clang] [libc] [libcxx] [libc][libcxx] Support for building libc++ against LLVM libc (PR #99287)

[Joseph Huber via libcxx-commits]

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@@ -293,6 +293,7 @@ option(LIBCXX_ENABLE_THREADS "Build libc++ with support for threads." ON)
 option(LIBCXX_ENABLE_MONOTONIC_CLOCK
   "Build libc++ with support for a monotonic clock.
    This option may only be set to OFF when LIBCXX_ENABLE_THREADS=OFF." ON)
+option(LIBCXX_USE_LLVM_LIBC "Build libc++ against LLVM libc." OFF)
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jhuber6 wrote:

But I don't think that config easily exposes what we're trying to express, since you could say `llvm-libc` and it wouldn't disambiguate between `llvm-libc` installed on the system globally and `llvm-libc` that exists as a target inside the current CMake project. So, we'd still need a flag in that case.

https://github.com/llvm/llvm-project/pull/99287