[mlir] [openmp] [lld] [libc] [llvm] [libcxx] [flang] [clang] [lldb] [compiler-rt] [clang-tools-extra] [libc++][streams] P1759R6: Native handles and file streams (PR #76632)

[via llvm-commits]

zeroomega wrote:

Hi, this change breaks libcxx test on Windows due to unable to find "unistd.h" file (which doesn't exist on msvc based environment).

Failed test message and failed commandline: 

```
********************
Failed Tests (8):
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/filebuf.members/native_handle.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/filebuf/types.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/fstream.members/native_handle.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/fstream/types.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/ifstream.members/native_handle.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/ifstream/types.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/ofstream.members/native_handle.pass.cpp
  llvm-libc++-static-clangcl.cfg.in :: std/input.output/file.streams/fstreams/ofstream/types.pass.cpp
```

```
Exit Code: 1

Command Output (stdout):
--
# COMPILED WITH
C:/b/s/w/ir/x/w/llvm_build/./bin/clang-cl.exe C:\b\s\w\ir\x\w\llvm-llvm-project\libcxx\test\std\input.output\file.streams\fstreams\filebuf.members\native_handle.pass.cpp --driver-mode=g++ --target=x86_64-pc-windows-msvc -fms-runtime-lib=static -nostdinc++ -I C:/b/s/w/ir/x/w/llvm_build/include/c++/v1 -I C:/b/s/w/ir/x/w/llvm_build/include/x86_64-pc-windows-msvc/c++/v1 -I C:/b/s/w/ir/x/w/llvm-llvm-project/libcxx/test/support -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_STDIO_ISO_WIDE_SPECIFIERS -DNOMINMAX -std=c++26 -Werror -Wall -Wctad-maybe-unsupported -Wextra -Wshadow -Wundef -Wunused-template -Wno-unused-command-line-argument -Wno-attributes -Wno-pessimizing-move -Wno-noexcept-type -Wno-atomic-alignment -Wno-reserved-module-identifier -Wdeprecated-copy -Wdeprecated-copy-dtor -Wno-user-defined-literals -Wno-tautological-compare -Wsign-compare -Wunused-variable -Wunused-parameter -Wunreachable-code -Wno-unused-local-typedef -Wno-local-type-template-args -Wno-c++11-extensions -Wno-unknown-pragmas -Wno-pass-failed -Wno-mismatched-new-delete -Wno-redundant-move -Wno-self-move -D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER -D_LIBCPP_ENABLE_EXPERIMENTAL -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_NONE -Werror=thread-safety -Wuser-defined-warnings  -llibc++experimental -nostdlib -L C:/b/s/w/ir/x/w/llvm_build/./lib/x86_64-pc-windows-msvc -llibc++ -llibcpmt -o C:\b\s\w\ir\x\w\llvm_build\runtimes\runtimes-x86_64-pc-windows-msvc-bins\test\std\input.output\file.streams\fstreams\filebuf.members\Output\native_handle.pass.cpp.dir\t.tmp.exe
# executed command: C:/b/s/w/ir/x/w/llvm_build/./bin/clang-cl.exe 'C:\b\s\w\ir\x\w\llvm-llvm-project\libcxx\test\std\input.output\file.streams\fstreams\filebuf.members\native_handle.pass.cpp' --driver-mode=g++ --target=x86_64-pc-windows-msvc -fms-runtime-lib=static -nostdinc++ -I C:/b/s/w/ir/x/w/llvm_build/include/c++/v1 -I C:/b/s/w/ir/x/w/llvm_build/include/x86_64-pc-windows-msvc/c++/v1 -I C:/b/s/w/ir/x/w/llvm-llvm-project/libcxx/test/support -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_STDIO_ISO_WIDE_SPECIFIERS -DNOMINMAX -std=c++26 -Werror -Wall -Wctad-maybe-unsupported -Wextra -Wshadow -Wundef -Wunused-template -Wno-unused-command-line-argument -Wno-attributes -Wno-pessimizing-move -Wno-noexcept-type -Wno-atomic-alignment -Wno-reserved-module-identifier -Wdeprecated-copy -Wdeprecated-copy-dtor -Wno-user-defined-literals -Wno-tautological-compare -Wsign-compare -Wunused-variable -Wunused-parameter -Wunreachable-code -Wno-unused-local-typedef -Wno-local-type-template-args -Wno-c++11-extensions -Wno-unknown-pragmas -Wno-pass-failed -Wno-mismatched-new-delete -Wno-redundant-move -Wno-self-move -D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER -D_LIBCPP_ENABLE_EXPERIMENTAL -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_NONE -Werror=thread-safety -Wuser-defined-warnings -llibc++experimental -nostdlib -L C:/b/s/w/ir/x/w/llvm_build/./lib/x86_64-pc-windows-msvc -llibc++ -llibcpmt -o 'C:\b\s\w\ir\x\w\llvm_build\runtimes\runtimes-x86_64-pc-windows-msvc-bins\test\std\input.output\file.streams\fstreams\filebuf.members\Output\native_handle.pass.cpp.dir\t.tmp.exe'
# .---command stderr------------
# | In file included from C:\b\s\w\ir\x\w\llvm-llvm-project\libcxx\test\std\input.output\file.streams\fstreams\filebuf.members\native_handle.pass.cpp:24:
# | In file included from C:\b\s\w\ir\x\w\llvm-llvm-project\libcxx\test\std\input.output\file.streams\fstreams\filebuf.members\../native_handle_test_helpers.h:33:
# | C:/b/s/w/ir/x/w/llvm-llvm-project/libcxx/test/support\check_assertion.h:22:10: fatal error: 'unistd.h' file not found
# |    22 | #include <unistd.h>
# |       |          ^~~~~~~~~~
# | 1 error generated.
# `-----------------------------
# error: command failed with exit status: 1

--
```



Failed build task: https://ci.chromium.org/ui/p/fuchsia/builders/toolchain.ci/clang-windows-x64/b8759750519305630833/overview

Could you revert your change and reland it after fixing it please?
C.C. @petrhosek 

https://github.com/llvm/llvm-project/pull/76632