qtwebengine fails to build with python error

Qt 5.11.0 stopped building with an error on component qtwebengine.

Config
D:\qt-everywhere-src-5.11.0\qtbase\configure.bat -top-level -opengl desktop -opensource -mp -confirm-license -prefix D:\qt\5_11_0 -icu -I D:\icu\include -L D:\icu\lib64

stdout text:
C:\Python27-32\python.exe ../../../../../qt-everywhere-src-5.11.0/qtwebengine/src/3rdparty/chromium/third_party/WebKit/Source/build/scripts/core/css/properties/make_css_property_subclasses.py ../../../../../qt-everywhere-src-5.11.0/qtwebengine/src/3rdparty/chromium/third_party/WebKit/Source/core/css/CSSProperties.json5 ../../../../../qt-everywhere-src-5.11.0/qtwebengine/src/3rdparty/chromium/third_party/WebKit/Source/core/css/ComputedStyleFieldAliases.json5 ../../../../../qt-everywhere-src-5.11.0/qtwebengine/src/3rdparty/chromium/third_party/WebKit/Source/core/css/properties/CSSPropertyMethods.json5 --output_dir gen/blink/core/css/properties/longhands --gperf gperf.exe
Traceback (most recent call last):
File "../../../../../qt-everywhere-src-5.11.0/qtwebengine/src/3rdparty/chromium/third_party/WebKit/Source/build/scripts/core/css/properties/make_css_property_subclasses.py", line 10, in <module>
import json5_generator
File "../../../../../qt-everywhere-src-5.11.0/qtwebengine/src/3rdparty/chromium/third_party/WebKit/Source/build/scripts/core/css/properties\../../..\json5_generator.py", line 65, in <module>
from blinkpy.common.name_style_converter import NameStyleConverter
ImportError: No module named name_style_converter

stderr text:
Set the LLVM_INSTALL_DIR environment variable to configure clang location (required to build qdoc).
.....
Project MESSAGE: Running: D:\qt-build\qtwebengine\src\3rdparty\chromium\tools\gn\out\Release\gn.exe gen D:\qt-build\qtwebengine\src\core\release --script-executable=C:\Python27-32\python.exe --args="use_qt=true is_component_build=false is_shared=true enable_nacl=false enable_remoting=false enable_reporting=false enable_web_speech=false use_allocator_shim=false use_allocator=\"none\" v8_use_external_startup_data=false treat_warnings_as_errors=false enable_swiftshader=false use_custom_libcxx=false enable_basic_printing=true enable_print_preview=true enable_pdf=true enable_plugins=true enable_widevine=true enable_spellcheck=true enable_webrtc=true enable_precompiled_headers=true is_debug=false symbol_level=0 remove_webcore_debug_symbols=true remove_v8base_debug_symbols=true v8_use_snapshot=true is_clang=false use_sysroot=false use_kerberos=true enable_session_service=false ninja_use_custom_environment_files=false is_multi_dll_chrome=false win_linker_timing=true is_win_fastlink=false use_incremental_linking=false visual_studio_version=2017 visual_studio_path=\"C:/Program Files ^(x86)/Microsoft Visual Studio/2017/Professional\" windows_sdk_path=\"C:/Program Files ^(x86)/Windows Kits/10\" target_cpu=\"x64\" qtwebengine_target=\"D:\qt-build\qtwebengine\src\core\release:QtWebEngineCore\"" --root=D:\qt-everywhere-src-5.11.0\qtwebengine\src\3rdparty\chromium

Microsoft (R) Program Maintenance Utility Version 14.14.26429.4
Copyright (C) Microsoft Corporation. All rights reserved.

Microsoft (R) Program Maintenance Utility Version 14.14.26429.4
Copyright (C) Microsoft Corporation. All rights reserved.

Microsoft (R) Program Maintenance Utility Version 14.14.26429.4
Copyright (C) Microsoft Corporation. All rights reserved.

NMAKE : fatal error U1077: 'call' : return code '0x1'
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.14.26428\bin\HostX64\x64\nmake.exe"' : return code '0x2'