[libcxx] [llvm] [libc++][C++03] Use `__cxx03/` headers in C++03 mode (PR #109002)

[Sean Perry via llvm-commits]

perry-ca wrote:

@philnik777 I noticed a few of the changes from `#include <foo>` to `#include <__cxx03/foo>` are now including files that don't exist.  I did a quick check with grep and found these headers are being included that don't exist.

- __cxx03/android/api-level.h
- __cxx03/__external_threading
- __cxx03/stdarg.h
- __cxx03/threads.h
- __cxx03/time.h
- __cxx03/unistd.h

I realize this is still a work in progress.  I hope this information helps.


https://github.com/llvm/llvm-project/pull/109002