[libc] [llvm] [libc] Move libc_errno.h to libc/src/__support and make LIBC_ERRNO_MODE_SYSTEM to be header-only. (PR #143187)

[Alexey Samsonov via llvm-commits]

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@@ -0,0 +1,20 @@
+//===-- Common defines for sharing LLVM libc with LLVM projects -*- C++ -*-===//
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vonosmas wrote:

If this header is retained, you'd need to include it in `libcxx_shared_headers` in Bazel build.

https://github.com/llvm/llvm-project/pull/143187