Build QtWebEngine with Python3.

[jiapei1000]

I strictly followed https://www.linuxfromscratch.org/blfs/view/svn/x/qtwebengine.html, and trying to build QtWebEngine from source with Python3, but I got the following ERROR info:

[170/14020] /usr/bin/g++ -MMD -MF obj/content/common/mojo_bindings/frame.mojom.o.d -DCONTENT_IMPLEMENTATION=1 -DUSE_UDEV -DUSE_AURA=1 -DUSE_NSS_CERTS=1 -DUSE_OZONE=1 -DOFFICIAL_BUILD -DTOOLKIT_QT -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -DNO_UNWIND_TABLES -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DGL_GLEXT_PROTOTYPES -DUSE_GLX -DUSE_EGL -DUSING_SYSTEM_ICU=1 -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_STATIC -DUCHAR_TYPE=uint16_t -DSK_CODEC_DECODES_PNG -DSK_CODEC_DECODES_WEBP -DSK_ENCODE_PNG -DSK_ENCODE_WEBP -DSK_USER_CONFIG_HEADER=\"../../skia/config/SkUserConfig.h\" -DSK_GL -DSK_CODEC_DECODES_JPEG -DSK_ENCODE_JPEG -DSK_USE_LIBGIFCODEC -DSK_VULKAN_HEADER=\"../../skia/config/SkVulkanConfig.h\" -DSK_VULKAN=1 -DSK_SUPPORT_GPU=1 -DSK_GPU_WORKAROUNDS_HEADER=\"gpu/config/gpu_driver_bug_workaround_autogen.h\" -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -DCRASHPAD_ZLIB_SOURCE_EXTERNAL -DUSE_SYSTEM_ZLIB=1 -DWEBRTC_NON_STATIC_TRACE_EVENT_HANDLERS=0 -DWEBRTC_CHROMIUM_BUILD -DWEBRTC_POSIX -DWEBRTC_LINUX -DABSL_ALLOCATOR_NOTHROW=1 -DWEBRTC_USE_BUILTIN_ISAC_FIX=0 -DWEBRTC_USE_BUILTIN_ISAC_FLOAT=1 -DWEBRTC_USE_X11 -DWEBRTC_USE_X11 -DHAVE_SCTP -DNO_MAIN_THREAD_WRAPPING -DLEVELDB_PLATFORM_CHROMIUM=1 -DLEVELDB_PLATFORM_CHROMIUM=1 -Igen -I../../../../src/3rdparty/chromium -I../../../../src/3rdparty/chromium/third_party/perfetto/include -Igen/third_party/perfetto/build_config -Igen/third_party/perfetto -Igen -Igen -Igen -Igen -Igen -Igen -Igen -I../../../../src/3rdparty/chromium/third_party/vulkan_headers/include -Igen -I../../../../src/3rdparty/chromium/third_party/libyuv/include -I../../../../src/3rdparty/chromium/third_party/jsoncpp/source/include -Igen -Igen -Igen -Igen -Igen -Igen -Igen -I../../../../src/3rdparty/chromium/third_party/khronos -I../../../../src/3rdparty/chromium/gpu -Igen/third_party/dawn/src/include -I../../../../src/3rdparty/chromium/third_party/dawn/src/include -I../../../../src/3rdparty/chromium/third_party/abseil-cpp -I../../../../src/3rdparty/chromium/third_party/boringssl/src/include -I../../../../src/3rdparty/chromium/third_party/protobuf/src -Igen/protoc_out -I../../../../src/3rdparty/chromium/third_party/ced/src -I../../../../src/3rdparty/chromium/third_party/skia -I../../../../src/3rdparty/chromium/third_party/libgifcodec -I../../../../src/3rdparty/chromium/third_party/vulkan/include -I../../../../src/3rdparty/chromium/third_party/vulkan_headers/include -I../../../../src/3rdparty/chromium/third_party/protobuf/src -I../../../../src/3rdparty/chromium/third_party/crashpad/crashpad -I../../../../src/3rdparty/chromium/third_party/crashpad/crashpad/compat/non_mac -I../../../../src/3rdparty/chromium/third_party/crashpad/crashpad/compat/linux -I../../../../src/3rdparty/chromium/third_party/crashpad/crashpad/compat/non_win -I../../../../src/3rdparty/chromium/third_party/webrtc_overrides -I../../../../src/3rdparty/chromium/third_party/webrtc -Igen/third_party/webrtc -I../../../../src/3rdparty/chromium/third_party/mesa_headers -I../../../../src/3rdparty/chromium/third_party/libwebm/source -I../../../../src/3rdparty/chromium/third_party/leveldatabase -I../../../../src/3rdparty/chromium/third_party/leveldatabase/src -I../../../../src/3rdparty/chromium/third_party/leveldatabase/src/include -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -fno-unwind-tables -fno-asynchronous-unwind-tables -fPIC -pipe -pthread -m64 -Wall -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -Wno-unused-local-typedefs -Wno-maybe-uninitialized -Wno-deprecated-declarations -fno-delete-null-pointer-checks -Wno-comments -Wno-packed-not-aligned -Wno-dangling-else -Wno-missing-field-initializers -Wno-unused-parameter -O2 -fno-ident -fdata-sections -ffunction-sections -fno-omit-frame-pointer -g0 -fvisibility=hidden -I/usr/include/nss -I/usr/include/nspr -std=gnu++14 -Wno-narrowing -Wno-class-memaccess -Wno-attributes -Wno-class-memaccess -Wno-subobject-linkage -Wno-invalid-offsetof -Wno-return-type -Wno-deprecated-copy -fno-exceptions -fno-rtti -fvisibility-inlines-hidden -Wno-deprecated-declarations -c gen/content/common/frame.mojom.cc -o obj/content/common/mojo_bindings/frame.mojom.o
ninja: build stopped: subcommand failed.
make[3]: *** [Makefile.gn_run:562: run_ninja] Error 1
make[3]: Leaving directory '....../qtwebengine-5.15.11/build/src/core'
make[2]: *** [Makefile:82: sub-gn_run-pro-make_first] Error 2
make[2]: Leaving directory '....../qtwebengine-5.15.11/build/src/core'
make[1]: *** [Makefile:80: sub-core-make_first] Error 2
make[1]: Leaving directory '....../qtwebengine-5.15.11/build/src'
make: *** [Makefile:49: sub-src-make_first] Error 2

Should I use my manually installed ninja (pip installed) ? or the ninja coming with QtWebEngine under 3rdparty ??

Cheers

[jsulm]

@jiapei1000 Please post the actual error - it should be somewhere above of what you posted.