ninja: Entering directory `out/gn'
[1/5852] AR lib/libLLVMSupport.a
[2/5852] AR lib/libgtest_main.a
[3/5852] ACTION //libcxx/include:write_config_site(//llvm/utils/gn/build/toolchain:unix)
FAILED: include/c++/v1/__config_site 
python3 ../../llvm/utils/gn/build/write_cmake_config.py -o include/c++/v1/__config_site ../../libcxx/include/__config_site.in _LIBCPP_ABI_FORCE_ITANIUM= _LIBCPP_ABI_FORCE_MICROSOFT= _LIBCPP_ABI_VERSION=1 _LIBCPP_ASSERTION_SEMANTIC_DEFAULT=_LIBCPP_ASSERTION_SEMANTIC_HARDENING_DEPENDENT _LIBCPP_EXTRA_SITE_DEFINES= _LIBCPP_HAS_FILESYSTEM=1 _LIBCPP_HAS_THREADS=1 _LIBCPP_HAS_MONOTONIC_CLOCK=1 _LIBCPP_HAS_MUSL_LIBC= _LIBCPP_HAS_THREAD_API_PTHREAD= _LIBCPP_HAS_THREAD_API_EXTERNAL= _LIBCPP_HAS_THREAD_API_WIN32= _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS= _LIBCPP_HAS_VENDOR_AVAILABILITY_ANNOTATIONS= _LIBCPP_NO_VCRUNTIME= _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION= _LIBCPP_HAS_RANDOM_DEVICE=1 _LIBCPP_HAS_LOCALIZATION=1 _LIBCPP_HAS_UNICODE=1 _LIBCPP_HAS_WIDE_CHARACTERS=1 _LIBCPP_HAS_TERMINAL=1 _LIBCPP_INSTRUMENTED_WITH_ASAN= _LIBCPP_ABI_DEFINES= _LIBCPP_HARDENING_MODE_DEFAULT=_LIBCPP_HARDENING_MODE_NONE _LIBCPP_LIBC_PICOLIBC= _LIBCPP_LIBC_NEWLIB= _LIBCPP_PSTL_BACKEND_LIBDISPATCH= _LIBCPP_PSTL_BACKEND_SERIAL= _LIBCPP_PSTL_BACKEND_STD_THREAD=1 _LIBCPP_ABI_NAMESPACE=__1 _LIBCPP_HAS_TIME_ZONE_DATABASE=1
Traceback (most recent call last):
  File "/usr/local/google/home/thakis/src/llvm-project/out/gn/../../llvm/utils/gn/build/write_cmake_config.py", line 122, in <module>
    sys.exit(main())
             ~~~~^^
  File "/usr/local/google/home/thakis/src/llvm-project/out/gn/../../llvm/utils/gn/build/write_cmake_config.py", line 75, in main
    if values[var] == "0":
       ~~~~~~^^^^^
KeyError: '_LIBCPP_LIBC_LLVM_LIBC'
[4/5852] LINK ./bin/clang-tidy-confusable-chars-gen
[5/5852] LINK ./bin/lldb-argdumper
[6/5852] LINK ./bin/split-file
[7/5852] LINK obj/llvm/unittests/LineEditor/LineEditorTests
[8/5852] LINK ./bin/llvm-undname
[9/5852] LINK ./bin/not
[10/5852] LINK obj/llvm/unittests/Testing/Support/TestingSupportTests
[11/5852] LINK ./bin/FileCheck
[12/5852] LINK obj/llvm/unittests/Bitstream/BitstreamTests
[13/5852] LINK obj/llvm/unittests/Testing/ADT/TestingADTTests
[14/5852] LINK ./bin/yaml-bench
[15/5852] LINK obj/llvm/unittests/Support/DynamicLibrary/DynamicLibraryTests
[16/5852] LINK obj/llvm/unittests/Support/LSP/LSPTests
[17/5852] LINK obj/llvm/unittests/DebugInfo/MSF/DebugInfoMSFTests
[18/5852] LINK obj/llvm/unittests/FileCheck/FileCheckTests
[19/5852] LINK obj/llvm/unittests/Demangle/DemangleTests
[20/5852] LINK obj/llvm/unittests/DebugInfo/CodeView/DebugInfoCodeViewTests
[21/5852] LINK ./bin/lldb-tblgen
[22/5852] LINK obj/llvm/unittests/CAS/CASTests
[23/5852] LINK ./bin/llvm-min-tblgen
[24/5852] LINK ./bin/clang-tblgen
ninja: build stopped: subcommand failed.
Command '['ninja', '-C', 'out/gn']' returned non-zero exit status 1.