qt-everywhere-src-5.15.2 fails to build xcb plation

[Brownwrap]

@SGaist That's part of the problem. The source compiles, "make check" doesn't return any errors. "make installs" completes without and warnings and installs the platform it did make. I am trying to actually build octave. When I start octave, it says it can't find the xcb platorm, but list the ones that did build.

[Brownwrap]

@Brownwrap I have search this error and found many solutions, but none of them fit me:

Got keys from plugin meta data ("webgl")
QFactoryLoader::QFactoryLoader() checking directory path "/software7/depot/octave-f812dd8304d9/libexec/octave/9.0.0/exec/x86_64-pc-linux-gnu/platforms" ...
qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, webgl.

Aborted (core dumped)

[SGaist]

As suggested, look at the test logs. They will contain the information about the failure.

That said, are you sure you installed all the required development packages for the xcb backend to be built ?

[Brownwrap]

@Brownwrap As stated I went through the logs. The configure log, the make log, and the "make check" log. I only came here after spending a week on this. I built the xcb from source since the RHEL 7 version wasn't new enough. I build X11 and mesa from source, QT, and octave from source, but stumped on this issue. I search this issue online before posting here. I just thought someone here might have built it sucessfully.

[Brownwrap]

@SGaist Output of Configure:

Configure summary:

Build type: linux-g++ (x86_64, CPU features: mmx sse sse2)
Compiler: gcc 9.3.0
Configuration: sse2 aesni sse3 ssse3 sse4_1 sse4_2 avx avx2 avx512f avx512bw avx512cd avx512dq avx512er avx512ifma avx512pf avx512vbmi avx512vl compile_examples enable_new_dtags f16c largefile precompile_header rdrnd rdseed shani x86SimdAlways shared shared release c++11 c++14 c++17 c++1z concurrent dbus reduce_exports reduce_relocations stl
Build options:
Mode ................................... release
Optimize release build for size ........ no
Building shared libraries .............. yes
Using C standard ....................... C11
Using C++ standard ..................... C++17
Using ccache ........................... no
Using new DTAGS ........................ yes
Relocatable ............................ yes
Using precompiled headers .............. yes
Using LTCG ............................. no
Target compiler supports:
SSE .................................. SSE2 SSE3 SSSE3 SSE4.1 SSE4.2
AVX .................................. AVX AVX2
AVX512 ............................... F ER CD PF DQ BW VL IFMA VBMI
Other x86 ............................ AES F16C RDRAND SHA
Intrinsics without -mXXX option ...... yes
Build parts ............................ libs tools
Qt modules and options:
Qt Concurrent .......................... yes
Qt D-Bus ............................... yes
Qt D-Bus directly linked to libdbus .... yes
Qt Gui ................................. yes
Qt Network ............................. yes
Qt Sql ................................. yes
Qt Testlib ............................. yes
Qt Widgets ............................. yes
Qt Xml ................................. yes
Support enabled for:
Using pkg-config ....................... yes
udev ................................... no
Using system zlib ...................... yes
Zstandard support ...................... no
Qt Core:
DoubleConversion ....................... yes
Using system DoubleConversion ........ no
GLib ................................... yes
iconv .................................. no
ICU .................................... yes
Built-in copy of the MIME database ..... yes
Tracing backend ........................ <none>
Logging backends:
journald ............................. no
syslog ............................... no
slog2 ................................ no
PCRE2 .................................. yes
Using system PCRE2 ................... no
Qt Network:
getifaddrs() ........................... yes
IPv6 ifname ............................ yes
libproxy ............................... no
Linux AF_NETLINK ....................... yes
OpenSSL ................................ no
Qt directly linked to OpenSSL ........ no
OpenSSL 1.1 ............................ no
DTLS ................................... no
OCSP-stapling .......................... no
SCTP ................................... no
Use system proxies ..................... yes
GSSAPI ................................. yes
Qt Gui:
Accessibility .......................... yes
FreeType ............................... yes
Using system FreeType ................ yes
HarfBuzz ............................... yes
Using system HarfBuzz ................ yes
Fontconfig ............................. yes
Image formats:
GIF .................................. yes
ICO .................................. yes
JPEG ................................. yes
Using system libjpeg ............... yes
PNG .................................. yes
Using system libpng ................ yes
Text formats:
HtmlParser ........................... yes
CssParser ............................ yes
OdfWriter ............................ yes
MarkdownReader ....................... yes
Using system libmd4c ............... no
MarkdownWriter ....................... yes
EGL .................................... yes
OpenVG ................................. no
OpenGL:
Desktop OpenGL ....................... yes
OpenGL ES 2.0 ........................ no
OpenGL ES 3.0 ........................ no
OpenGL ES 3.1 ........................ no
OpenGL ES 3.2 ........................ no
Vulkan ................................. no
Session Management ..................... yes
Features used by QPA backends:
evdev .................................. yes
libinput ............................... no
INTEGRITY HID .......................... no
mtdev .................................. no
tslib .................................. no
xkbcommon .............................. no
X11 specific:
XLib ................................. yes
XCB Xlib ............................. yes
EGL on X11 ........................... yes
xkbcommon-x11 ........................ no
QPA backends:
DirectFB ............................... no
EGLFS .................................. yes
EGLFS details:
EGLFS OpenWFD ........................ no
EGLFS i.Mx6 .......................... no
EGLFS i.Mx6 Wayland .................. no
EGLFS RCAR ........................... no
EGLFS EGLDevice ...................... yes
EGLFS GBM ............................ yes
EGLFS VSP2 ........................... no
EGLFS Mali ........................... no
EGLFS Raspberry Pi ................... no
EGLFS X11 ............................ yes
LinuxFB ................................ yes
VNC .................................... yes
Qt Sql:
SQL item models ........................ yes
Qt Widgets:
GTK+ ................................... no
Styles ................................. Fusion Windows
Qt PrintSupport:
CUPS ................................... no
Qt Sql Drivers:
DB2 (IBM) .............................. no
InterBase .............................. no
MySql .................................. no
OCI (Oracle) ........................... no
ODBC ................................... no
PostgreSQL ............................. yes
SQLite2 ................................ no
SQLite ................................. yes
Using system provided SQLite ......... no
TDS (Sybase) ........................... no
Qt Testlib:
Tester for item models ................. yes
Serial Port:
ntddmodm ............................... no
Qt SerialBus:
Socket CAN ............................. yes
Socket CAN FD .......................... yes
SerialPort Support ..................... yes
Further Image Formats:
JasPer ................................. no
MNG .................................... no
TIFF ................................... yes
Using system libtiff ................. no
WEBP ................................... yes
Using system libwebp ................. no
Qt QML:
QML network support .................... yes
QML debugging and profiling support .... yes
QML just-in-time compiler .............. yes
QML sequence object .................... yes
QML XML http request ................... yes
QML Locale ............................. yes
Qt QML Models:
QML list model ......................... yes
QML delegate model ..................... yes
Qt Quick:
Direct3D 12 ............................ no
AnimatedImage item ..................... yes
Canvas item ............................ yes
Support for Qt Quick Designer .......... yes
Flipable item .......................... yes
GridView item .......................... yes
ListView item .......................... yes
TableView item ......................... yes
Path support ........................... yes
PathView item .......................... yes
Positioner items ....................... yes
Repeater item .......................... yes
ShaderEffect item ...................... yes
Sprite item ............................ yes
QtQuick3D:
Assimp ................................. yes
System Assimp .......................... no
Qt Scxml:
ECMAScript data model for QtScxml ...... yes
Qt Gamepad:
SDL2 ................................... no
Qt 3D:
Assimp ................................. yes
System Assimp .......................... no
Output Qt3D GL traces .................. no
Use SSE2 instructions .................. yes
Use AVX2 instructions .................. no
Aspects:
Render aspect ........................ yes
Input aspect ......................... yes
Logic aspect ......................... yes
Animation aspect ..................... yes
Extras aspect ........................ yes
Qt 3D Renderers:
OpenGL Renderer ........................ yes
RHI Renderer ........................... no
Qt 3D GeometryLoaders:
Autodesk FBX ........................... no
Qt Wayland Drivers:
EGL .................................... yes
Raspberry Pi ........................... no
XComposite EGL ......................... no
XComposite GLX ......................... no
DRM EGL ................................ yes
libhybris EGL .......................... no
Linux dma-buf server buffer integration . no
Vulkan-based server buffer integration . no
Shm emulation server buffer integration . yes
Qt Wayland Client Shell Integrations:
xdg-shell .............................. yes
xdg-shell unstable v5 (deprecated) ..... yes
xdg-shell unstable v6 .................. yes
ivi-shell .............................. yes
wl-shell (deprecated) .................. yes
Qt Wayland Client ........................ yes
Qt Wayland Compositor .................... yes
Qt Wayland Compositor Layer Plugins:
VSP2 hardware layer integration ........ no
Qt Bluetooth:
BlueZ .................................. no
BlueZ Low Energy ....................... no
Linux Crypto API ....................... no
Native Win32 Bluetooth ................. no
WinRT Bluetooth API (desktop & UWP) .... no
WinRT advanced bluetooth low energy API (desktop & UWP) . no
Qt Sensors:
sensorfw ............................... no
Qt Quick Controls 2:
Styles ................................. Default Fusion Imagine Material Universal
Qt Quick Templates 2:
Hover support .......................... yes
Multi-touch support .................... yes
Qt Positioning:
Gypsy GPS Daemon ....................... no
WinRT Geolocation API .................. no
Qt Location:
Qt.labs.location experimental QML plugin . yes
Geoservice plugins:
OpenStreetMap ........................ yes
HERE ................................. yes
Esri ................................. yes
Mapbox ............................... yes
MapboxGL ............................. yes
Itemsoverlay ......................... yes
QtXmlPatterns:
XML schema support ..................... yes
Qt Multimedia:
ALSA ................................... no
GStreamer 1.0 .......................... no
GStreamer 0.10 ......................... no
Video for Linux ........................ yes
OpenAL ................................. no
PulseAudio ............................. no
Resource Policy (libresourceqt5) ....... no
Windows Audio Services ................. no
DirectShow ............................. no
Windows Media Foundation ............... no
Qt TextToSpeech:
Flite .................................. no
Flite with ALSA ........................ no
Speech Dispatcher ...................... no
Qt Tools:
Qt Assistant ........................... yes
Qt Designer ............................ yes
Qt Distance Field Generator ............ yes
kmap2qmap .............................. yes
Qt Linguist ............................ yes
Mac Deployment Tool .................... no
makeqpf ................................ yes
pixeltool .............................. yes
qdbus .................................. yes
qev .................................... yes
Qt Attributions Scanner ................ yes
qtdiag ................................. yes
qtpaths ................................ yes
qtplugininfo ........................... yes
Windows deployment tool ................ no
WinRT Runner Tool ...................... no
Qt Tools:
QDoc ................................... yes

Note: Also available for Linux: linux-clang linux-icc

WARNING: Feature system-xcb-xinput is insignificant in this configuration, ignoring related command line option(s).

Qt is now configured for building. Just run 'gmake'.
Once everything is built, you must run 'gmake install'.
Qt will be installed into '/software7/depot/qt-everywhere-src-5.15.2'.

Prior to reconfiguration, make sure you remove any leftovers from
the previous build.

[ramos@hal4500 qt-everywhere-src-5.15.2]$
[ramos@hal4500 qt-everywhere-src-5.15.2]$ vi configure=output.log
Itemsoverlay ......................... yes
QtXmlPatterns:
XML schema support ..................... yes
Qt Multimedia:
ALSA ................................... no
GStreamer 1.0 .......................... no
GStreamer 0.10 ......................... no
Video for Linux ........................ yes
OpenAL ................................. no
PulseAudio ............................. no
Resource Policy (libresourceqt5) ....... no
Windows Audio Services ................. no
DirectShow ............................. no
Windows Media Foundation ............... no
Qt TextToSpeech:
Flite .................................. no
Flite with ALSA ........................ no
Speech Dispatcher ...................... no
Qt Tools:
Qt Assistant ........................... yes
Qt Designer ............................ yes
Qt Distance Field Generator ............ yes
kmap2qmap .............................. yes
Qt Linguist ............................ yes
Mac Deployment Tool .................... no
makeqpf ................................ yes
pixeltool .............................. yes
qdbus .................................. yes
qev .................................... yes
Qt Attributions Scanner ................ yes
qtdiag ................................. yes
qtpaths ................................ yes
qtplugininfo ........................... yes
Windows deployment tool ................ no
WinRT Runner Tool ...................... no
Qt Tools:
QDoc ................................... yes

Note: Also available for Linux: linux-clang linux-icc

WARNING: Feature system-xcb-xinput is insignificant in this configuration, ignoring related command line option(s).

Qt is now configured for building. Just run 'gmake'.
Once everything is built, you must run 'gmake install'.
Qt will be installed into '/software7/depot/qt-everywhere-src-5.15.2'.

[SGaist]

From the looks of your summary, you are missing xkbcommon.

[Brownwrap]

@Brownwrap Well, I built that missing library, but the same result:

Configure summary:

Build type: linux-g++ (x86_64, CPU features: mmx sse sse2)
Compiler: gcc 9.3.0
Configuration: sse2 aesni sse3 ssse3 sse4_1 sse4_2 avx avx2 avx512f avx512bw avx512cd avx512dq avx512er avx512ifma avx512pf avx512vbmi avx512vl compile_examples enable_new_dtags f16c largefile precompile_header rdrnd rdseed shani x86SimdAlways shared shared release c++11 c++14 c++17 c++1z concurrent dbus reduce_exports reduce_relocations stl
Build options:
Mode ................................... release
Optimize release build for size ........ no
Building shared libraries .............. yes
Using C standard ....................... C11
Using C++ standard ..................... C++17
Using ccache ........................... no
Using new DTAGS ........................ yes
Relocatable ............................ yes
Using precompiled headers .............. yes
Using LTCG ............................. no
Target compiler supports:
SSE .................................. SSE2 SSE3 SSSE3 SSE4.1 SSE4.2
AVX .................................. AVX AVX2
AVX512 ............................... F ER CD PF DQ BW VL IFMA VBMI
Other x86 ............................ AES F16C RDRAND SHA
Intrinsics without -mXXX option ...... yes
Build parts ............................ libs tools
Qt modules and options:
Qt Concurrent .......................... yes
Qt D-Bus ............................... yes
Qt D-Bus directly linked to libdbus .... yes
Qt Gui ................................. yes
Qt Network ............................. yes
Qt Sql ................................. yes
Qt Testlib ............................. yes
Qt Widgets ............................. yes
Qt Xml ................................. yes
Support enabled for:
Using pkg-config ....................... yes
udev ................................... no
Using system zlib ...................... yes
Zstandard support ...................... no
Qt Core:
DoubleConversion ....................... yes
Using system DoubleConversion ........ no
GLib ................................... yes
iconv .................................. no
ICU .................................... yes
Built-in copy of the MIME database ..... yes
Tracing backend ........................ <none>
Logging backends:
journald ............................. no
syslog ............................... no
slog2 ................................ no
PCRE2 .................................. yes
Using system PCRE2 ................... no
Qt Network:
getifaddrs() ........................... yes
IPv6 ifname ............................ yes
libproxy ............................... no
Linux AF_NETLINK ....................... yes
OpenSSL ................................ no
Qt directly linked to OpenSSL ........ no
OpenSSL 1.1 ............................ no
DTLS ................................... no
OCSP-stapling .......................... no
SCTP ................................... no
Use system proxies ..................... yes
GSSAPI ................................. yes
Qt Gui:
Accessibility .......................... yes
FreeType ............................... yes
Using system FreeType ................ yes
HarfBuzz ............................... yes
Using system HarfBuzz ................ yes
Fontconfig ............................. yes
Image formats:
GIF .................................. yes
ICO .................................. yes
JPEG ................................. yes
Using system libjpeg ............... yes
PNG .................................. yes
Using system libpng ................ yes
Text formats:
HtmlParser ........................... yes
CssParser ............................ yes
OdfWriter ............................ yes
MarkdownReader ....................... yes
Using system libmd4c ............... no
MarkdownWriter ....................... yes
EGL .................................... yes
OpenVG ................................. no
OpenGL:
Desktop OpenGL ....................... yes
OpenGL ES 2.0 ........................ no
OpenGL ES 3.0 ........................ no
OpenGL ES 3.1 ........................ no
OpenGL ES 3.2 ........................ no
Vulkan ................................. no
Session Management ..................... yes
Features used by QPA backends:
evdev .................................. yes
libinput ............................... no
INTEGRITY HID .......................... no
mtdev .................................. no
tslib .................................. no
xkbcommon .............................. yes
X11 specific:
XLib ................................. yes
XCB Xlib ............................. yes
EGL on X11 ........................... yes
xkbcommon-x11 ........................ yes
QPA backends:
DirectFB ............................... no
EGLFS .................................. yes
EGLFS details:
EGLFS OpenWFD ........................ no
EGLFS i.Mx6 .......................... no
EGLFS i.Mx6 Wayland .................. no
EGLFS RCAR ........................... no
EGLFS EGLDevice ...................... yes
EGLFS GBM ............................ yes
EGLFS VSP2 ........................... no
EGLFS Mali ........................... no
EGLFS Raspberry Pi ................... no
EGLFS X11 ............................ yes
LinuxFB ................................ yes
VNC .................................... yes
Qt Sql:
SQL item models ........................ yes
Qt Widgets:
GTK+ ................................... no
Styles ................................. Fusion Windows
Qt PrintSupport:
CUPS ................................... no
Qt Sql Drivers:
DB2 (IBM) .............................. no
InterBase .............................. no
MySql .................................. no
OCI (Oracle) ........................... no
ODBC ................................... no
PostgreSQL ............................. yes
SQLite2 ................................ no
SQLite ................................. yes
Using system provided SQLite ......... no
TDS (Sybase) ........................... no
Qt Testlib:
Tester for item models ................. yes
Serial Port:
ntddmodm ............................... no
Qt SerialBus:
Socket CAN ............................. yes
Socket CAN FD .......................... yes
SerialPort Support ..................... yes
Further Image Formats:
JasPer ................................. no
MNG .................................... no
TIFF ................................... yes
Using system libtiff ................. no
WEBP ................................... yes
Using system libwebp ................. no
Qt QML:
QML network support .................... yes
QML debugging and profiling support .... yes
QML just-in-time compiler .............. yes
QML sequence object .................... yes
QML XML http request ................... yes
QML Locale ............................. yes
Qt QML Models:
QML list model ......................... yes
QML delegate model ..................... yes
Qt Quick:
Direct3D 12 ............................ no
AnimatedImage item ..................... yes
Canvas item ............................ yes
Support for Qt Quick Designer .......... yes
Flipable item .......................... yes
GridView item .......................... yes
ListView item .......................... yes
TableView item ......................... yes
Path support ........................... yes
PathView item .......................... yes
Positioner items ....................... yes
Repeater item .......................... yes
ShaderEffect item ...................... yes
Sprite item ............................ yes
QtQuick3D:
Assimp ................................. yes
System Assimp .......................... no
Qt Scxml:
ECMAScript data model for QtScxml ...... yes
Qt Gamepad:
SDL2 ................................... no
Qt 3D:
Assimp ................................. yes
System Assimp .......................... no
Output Qt3D GL traces .................. no
Use SSE2 instructions .................. yes
Use AVX2 instructions .................. no
Aspects:
Render aspect ........................ yes
Input aspect ......................... yes
Logic aspect ......................... yes
Animation aspect ..................... yes
Extras aspect ........................ yes
Qt 3D Renderers:
OpenGL Renderer ........................ yes
RHI Renderer ........................... no
Qt 3D GeometryLoaders:
Autodesk FBX ........................... no
Qt Wayland Drivers:
EGL .................................... yes
Raspberry Pi ........................... no
XComposite EGL ......................... no
XComposite GLX ......................... no
DRM EGL ................................ yes
libhybris EGL .......................... no
Linux dma-buf server buffer integration . no
Vulkan-based server buffer integration . no
Shm emulation server buffer integration . yes
Qt Wayland Client Shell Integrations:
xdg-shell .............................. yes
xdg-shell unstable v5 (deprecated) ..... yes
xdg-shell unstable v6 .................. yes
ivi-shell .............................. yes
wl-shell (deprecated) .................. yes
Qt Wayland Client ........................ yes
Qt Wayland Compositor .................... yes
Qt Wayland Compositor Layer Plugins:
VSP2 hardware layer integration ........ no
Qt Bluetooth:
BlueZ .................................. no
BlueZ Low Energy ....................... no
Linux Crypto API ....................... no
Native Win32 Bluetooth ................. no
WinRT Bluetooth API (desktop & UWP) .... no
WinRT advanced bluetooth low energy API (desktop & UWP) . no
Qt Sensors:
sensorfw ............................... no
Qt Quick Controls 2:
Styles ................................. Default Fusion Imagine Material Universal
Qt Quick Templates 2:
Hover support .......................... yes
Multi-touch support .................... yes
Qt Positioning:
Gypsy GPS Daemon ....................... no
WinRT Geolocation API .................. no
Qt Location:
Qt.labs.location experimental QML plugin . yes
Geoservice plugins:
OpenStreetMap ........................ yes
HERE ................................. yes
Esri ................................. yes
Mapbox ............................... yes
MapboxGL ............................. yes
Itemsoverlay ......................... yes
QtXmlPatterns:
XML schema support ..................... yes
Qt Multimedia:
ALSA ................................... no
GStreamer 1.0 .......................... no
GStreamer 0.10 ......................... no
Video for Linux ........................ yes
OpenAL ................................. no
PulseAudio ............................. no
Resource Policy (libresourceqt5) ....... no
Windows Audio Services ................. no
DirectShow ............................. no
Windows Media Foundation ............... no
Qt TextToSpeech:
Flite .................................. no
Flite with ALSA ........................ no
Speech Dispatcher ...................... no
Qt Tools:
Qt Assistant ........................... yes
Qt Designer ............................ yes
Qt Distance Field Generator ............ yes
kmap2qmap .............................. yes
Qt Linguist ............................ yes
Mac Deployment Tool .................... no
makeqpf ................................ yes
pixeltool .............................. yes
qdbus .................................. yes
qev .................................... yes
Qt Attributions Scanner ................ yes
qtdiag ................................. yes
qtpaths ................................ yes
qtplugininfo ........................... yes
Windows deployment tool ................ no
WinRT Runner Tool ...................... no
Qt Tools:
QDoc ................................... yes

Note: Also available for Linux: linux-clang linux-icc

[jsulm]

@Brownwrap said in qt-everywhere-src-5.15.2 fails to build xcb plation:

I built that missing library

How?
There is no need to build it by yourself. Simply install it from your Linux distribution packages and also install xkbcommon-dev.

[Brownwrap]

@jsulm Many of the packages I built, because the packages from RHEL 7 were too old.

[Cryptik]

@Brownwrap
So I am having a similar problem here... I have built Qt 5.15.2 for linux ARM and the configure, make, and make install steps go just fine. I did install the x11 dependencies and configure appears to show that it finds everything.

Features used by QPA backends:
  evdev .................................. yes
  libinput ............................... no
  INTEGRITY HID .......................... no
  mtdev .................................. no
  tslib .................................. no
  xkbcommon .............................. yes
  X11 specific:
    XLib ................................. yes
    XCB Xlib ............................. yes
    EGL on X11 ........................... yes
    xkbcommon-x11 ........................ yes
QPA backends:
  DirectFB ............................... no
  EGLFS .................................. yes
  EGLFS details:
    EGLFS OpenWFD ........................ no
    EGLFS i.Mx6 .......................... no
    EGLFS i.Mx6 Wayland .................. no
    EGLFS RCAR ........................... no
    EGLFS EGLDevice ...................... yes
    EGLFS GBM ............................ no
    EGLFS VSP2 ........................... no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... no
    EGLFS X11 ............................ yes
  LinuxFB ................................ yes
  VNC .................................... yes

I set up the environment and the output is as expected...

qmake -version
QMake version 3.1
Using Qt version 5.15.2 in /opt/Qt5.15.2/lib

which qmake
/opt/Qt5.15.2/bin/qmake

When trying to run one of the GUI tools, I get this error...

qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl.

Aborted (core dumped)

Spent just about three days on this and I am not getting anywhere.

Ultimately, I don't need to run the Qt GUI tools. I am trying to build QGroundControl from source and it requires Qt 5.15.2. After building and installing Qt, I then try to build

QGroundControl and get a similar qt X11 error as follows:
Project MESSAGE: Qt version 5.15.2
Project MESSAGE: Linux build
/usr/bin/ccache
Project MESSAGE: Found ccache, enabling
Project MESSAGE: Daily Build
Project MESSAGE: GIT_DESCRIBE v4.2.0-371-ga955232df
Project MESSAGE: QGroundControl APP_VERSION_STR VERSION v4.2.0-371-ga955232df 4.2.0.371
Project MESSAGE: Debug flavor
Project MESSAGE: Skipping support for Pairing
collect2 version 9.4.0
/usr/bin/ld.gold -plugin /usr/lib/gcc/aarch64-linux-gnu/9/liblto_plugin.so -plugin-opt=/usr/lib/gcc/aarch64-linux-gnu/9/lto-wrapper -plugin-opt=-fresolution=/tmp/ccCu4GFJ.res -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc --build-id --eh-frame-hdr --hash-style=gnu --as-needed -dynamic-linker /lib/ld-linux-aarch64.so.1 -X -EL -maarch64linux --fix-cortex-a53-843419 -pie -z now -z relro /usr/lib/gcc/aarch64-linux-gnu/9/../../../aarch64-linux-gnu/Scrt1.o /usr/lib/gcc/aarch64-linux-gnu/9/../../../aarch64-linux-gnu/crti.o /usr/lib/gcc/aarch64-linux-gnu/9/crtbeginS.o -L/usr/lib/gcc/aarch64-linux-gnu/9 -L/usr/lib/gcc/aarch64-linux-gnu/9/../../../aarch64-linux-gnu -L/usr/lib/gcc/aarch64-linux-gnu/9/../../../../lib -L/lib/aarch64-linux-gnu -L/lib/../lib -L/usr/lib/aarch64-linux-gnu -L/usr/lib/../lib -L/usr/lib/gcc/aarch64-linux-gnu/9/../../.. --version -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/aarch64-linux-gnu/9/crtendS.o /usr/lib/gcc/aarch64-linux-gnu/9/../../../aarch64-linux-gnu/crtn.o
Project MESSAGE: Using MAVLink dialect 'ardupilotmega'.
Project MESSAGE: Skipping support for Zeroconf (unsupported platform)
Project MESSAGE: Skipping support for AirMap (manual override from user_config.pri)
Project MESSAGE: Taisync disabled
Project MESSAGE: Microhard disabled
GNU gold (GNU Binutils for Ubuntu 2.34) 1.16
Copyright (C) 2020 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.
Project MESSAGE: Including support for video streaming
Project ERROR: Unknown module(s) in QT: x11extras

[Cryptik]

@Cryptik
Again, posting this here for others that may have the same problem that I did. I deleted my build folder and ran configure again but with a few extra parameters as follows:

../configure -debug -prefix /opt/Qt5.15.2 -opensource -nomake tests -skip webengine -qt-xcb -qt-xkbcommon

It seems that switching xcd and xkbcommon to qt versions fixed it for me. I can now launch the assistant and designer tools. The build of qgroundcontrol also now works.