I need to build QtWebEngine 6.2.1 on ubuntu 20.04. But, I do not know how to fix some error. please tell me how to do.

I clone code from [git://code.qt.io/qt/qtwebengine.git]

checkout to branch 6.2.1

run config command: /home/bh/Qt6.2/6.2.1/gcc_64/bin/qt-configure-module /home/bh/workSpace/qtwebengine – -DQT_FEATURE_webengine_proprietary_codecs=ON

out:

'/home/bh/Qt6.2/6.2.1/gcc_64/bin/qt-cmake-private' '-DQT_FEATURE_webengine_proprietary_codecs=ON' '/home/bh/workSpace/qtwebengine'
– Check for feature set changes
'qtwebengine_build' is changed from OFF to ON
CMake Warning at /home/bh/Qt6.2/6.2.1/gcc_64/lib/cmake/Qt6/QtSetup.cmake:265 (message):
Re-configuring in existing build folder. Some features will be
re-evaluated automatically.
Call Stack (most recent call first):
/home/bh/Qt6.2/6.2.1/gcc_64/lib/cmake/Qt6BuildInternals/Qt6BuildInternalsConfig.cmake:229 (include)
/home/bh/Qt6.2/6.2.1/gcc_64/lib/cmake/Qt6BuildInternals/Qt6BuildInternalsConfig.cmake:372 (qt_build_internals_set_up_private_api)
/home/bh/Qt6.2/6.2.1/gcc_64/lib/cmake/Qt6BuildInternals/Qt6BuildInternalsConfig.cmake:484 (qt_build_repo_begin)
CMakeLists.txt:37 (qt_build_repo)

– Could NOT find Gn: Found unsuitable version "1943 (90294ccd)", but required is exact version "6.2.1" (found /usr/local/bin/gn)
– Checking 'ulimit -n'
– Open files limit 1024
– Creating linker launcher
– Support check for QtWebEngine failed: Could not find all necessary libraries for qpa-xcb support. X11:YES LIBDRM:YES XCOMPOSITE:YES XCURSOR:YES XRANDR:YES XI:YES XPROTO:YES XSHMFENCE:YES XTST:YES
– The following packages have been found:

• Qt6BuildInternals (required version >= 6.2.1)
• Qt6CoreTools (required version >= 6.2.1)
• Qt6Core (required version >= 6.2.1)
• OpenGL
• XKB (required version >= 0.5.0), XKB API common to servers and clients., <http://xkbcommon.org>
• Vulkan
• Qt6GuiTools (required version >= 6.2.1)
• Qt6Gui (required version >= 6.2.1)
• Qt6WidgetsTools (required version >= 6.2.1)
• Qt6Widgets (required version >= 6.2.1)
• OpenSSL
• WrapOpenSSLHeaders
• Qt6Network (required version >= 6.2.1)
• WrapVulkanHeaders
• Qt6OpenGL (required version >= 6.2.1)
• Qt6Quick (required version >= 6.2.1)
• Qt6QmlTools (required version >= 6.2.1)
• Qt6Qml (required version >= 6.2.1)
• Qt6PrintSupport (required version >= 6.2.1)
• Qt6WebChannel (required version >= 6.2.1)
• Qt6Positioning (required version >= 6.2.1)
• Qt6QuickControls2 (required version >= 6.2.1)
• Qt6Test (required version >= 6.2.1)
• Qt6QuickWidgets (required version >= 6.2.1)
• Qt6QuickTest (required version >= 6.2.1)
• Qt6WebSockets (required version >= 6.2.1)
• Qt6Designer (required version >= 6.2.1)
• Qt6 (required version >= 6.2.1)
• Ninja (required version >= 1.7.2), Build tool, <https://ninja-build.org/>
• Python2 (required version >= 2.7.5)
• GPerf, Perfect hash function generator, <https://www.gnu.org/software/gperf/>
• BISON
• FLEX
• PkgConfig
• Snappy
• Nodejs (required version >= 10.19), JavaScript runtime environment that runs on the V8 engine, <https://nodejs.org/>

– The following OPTIONAL packages have not been found:

• Qt6QmlCompilerPlus
• Gn (required version == 6.2.1), Meta-build system, <https://gn.googlesource.com/gn/>

Configure summary:

Qt WebEngine:
Use system ninja ....................... yes
Use system gn .......................... no
Jumbo Build ............................ yes
Developer build ........................ no
Optional system libraries:
re2 .................................. yes
icu .................................. no
libwebp, libwebpmux and libwebpdemux . yes
opus ................................. yes
ffmpeg ............................... no
libvpx ............................... no
snappy ............................... yes
glib ................................. yes
zlib ................................. yes
minizip .............................. yes
libevent ............................. no
libxml2 and libxslt .................. no
lcms2 ................................ no
png .................................. no
jpeg ................................. no
harfbuzz ............................. no
freetype ............................. yes
libpci ............................... yes

WARNING: QtWebEngine won't be built. Could not find all necessary libraries for qpa-xcb support. X11:YES LIBDRM:YES XCOMPOSITE:YES XCURSOR:YES XRANDR:YES XI:YES XPROTO:YES XSHMFENCE:YES XTST:YES

– Configuring done
– Generating done
– Build files have been written to: /home/bh/workSpace/qtwebengine

and start build : ninja all

get error:

[1/1] Check QtWebEngine support
QtWebEngine will not be built: Could not find all necessary libraries for qpa-xcb support. X11:YES LIBDRM:YES XCOMPOSITE:YES XCURSOR:YES XRANDR:YES XI:YES XPROTO:YES XSHMFENCE:YES XTST:YES

Please tell me how to fix this error. thanks