Cross compilation and Qt configuration issue with Xlib

[X-Krys]

I'm trying to configure Qt to cross compile it for a different OS (Debian Stretch) than my host.

I built a toolchain using Crosstool-NG and have a copy of my target sysroot on my host.

I can't manage to get the EGLFS on X11 feature since Xlib test fails at config time.

Here the configure output:

Building on: linux-g++ (x86_64, CPU features: mmx sse sse2)
Building for: devices/linux-generic-g++ (x86_64, CPU features: mmx sse sse2)
Target compiler: gcc 8.2.0
Configuration: cross_compile use_gold_linker 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 shani x86SimdAlways shared rpath release c++11 c++14 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++1z
  Using ccache ........................... no
  Using gold linker ...................... yes
  Using new DTAGS ........................ 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
Qt modules and options:
  Qt Concurrent .......................... yes
  Qt D-Bus ............................... yes
  Qt D-Bus directly linked to libdbus .... no
  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 ................................... yes
  Using system zlib ...................... yes
Qt Core:
  DoubleConversion ....................... yes
    Using system DoubleConversion ........ no
  GLib ................................... yes
  iconv .................................. no
  ICU .................................... yes
  Tracing backend ........................ <none>
  Logging backends:
    journald ............................. yes
    syslog ............................... no
    slog2 ................................ no
  Using system PCRE2 ..................... no
Qt Network:
  getifaddrs() ........................... yes
  IPv6 ifname ............................ yes
  libproxy ............................... no
  Linux AF_NETLINK ....................... yes
  OpenSSL ................................ yes
    Qt directly linked to OpenSSL ........ no
  OpenSSL 1.1 ............................ yes
  DTLS ................................... yes
  SCTP ................................... no
  Use system proxies ..................... yes
Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ yes
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ no
  Fontconfig ............................. yes
  Image formats:
    GIF .................................. yes
    ICO .................................. yes
    JPEG ................................. yes
      Using system libjpeg ............... no
    PNG .................................. yes
      Using system libpng ................ 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 ............................... yes
  INTEGRITY HID .......................... no
  mtdev .................................. no
  tslib .................................. no
  xkbcommon .............................. yes
  X11 specific:
    XLib ................................. no
    XCB Xlib ............................. no
    EGL on 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 ............................ no
    EGLFS VSP2 ........................... no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... no
    EGLFS X11 ............................ no
  LinuxFB ................................ yes
  VNC .................................... yes
  Mir client ............................. no
  XCB:
    Using system-provided XCB libraries .. no
    XCB XKB .............................. no
    XCB XInput ........................... yes
    Native painting (experimental) ....... no
    GL integrations:
      GLX Plugin ......................... no
      EGL-X11 Plugin ..................... no
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 ............................. no
  SQLite2 ................................ no
  SQLite ................................. yes
    Using system provided SQLite ......... no
  TDS (Sybase) ........................... no
Qt Testlib:
  Tester for item models ................. yes
Qt SerialBus:
  Socket CAN ............................. yes
  Socket CAN FD .......................... yes
Qt QML:
  QML network support .................... yes
  QML debugging and profiling support .... yes
  QML sequence object .................... yes
  QML list model ......................... yes
  QML XML http request ................... yes
  QML Locale ............................. 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
Qt Scxml:
  ECMAScript data model for QtScxml ...... yes
Qt Gamepad:
  SDL2 ................................... no
Qt 3D:
  Assimp ................................. yes
  System Assimp .......................... no
  Output Qt3D Job traces ................. 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
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
  Shm emulation server buffer integration . 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
  WinRT Bluetooth 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 .......................... yes
  GStreamer 0.10 ......................... no
  Video for Linux ........................ yes
  OpenAL ................................. no
  PulseAudio ............................. yes
  Resource Policy (libresourceqt5) ....... no
  Windows Audio Services ................. no
  DirectShow ............................. no
  Windows Media Foundation ............... no
Qt Tools:
  QDoc ................................... no
Qt WebEngine:
  Embedded build ......................... yes
  Pepper Plugins ......................... no
  Printing and PDF ....................... no
  Proprietary Codecs ..................... no
  Spellchecker ........................... yes
  Native Spellchecker .................... no
  WebRTC ................................. no
  Use System Ninja ....................... no
  Geolocation ............................ yes
  WebChannel support ..................... yes
  Use v8 snapshot ........................ yes
  Kerberos Authentication ................ no
  Building v8 snapshot supported ......... yes
  Use ALSA ............................... no
  Use PulseAudio ......................... yes
  Optional system libraries used:
    re2 .................................. no
    icu .................................. no
    libwebp, libwebpmux and libwebpdemux . no
    opus ................................. no
    ffmpeg ............................... no
    libvpx ............................... no
    snappy ............................... no
    glib ................................. yes
    zlib ................................. yes
    minizip .............................. no
    libevent ............................. no
    jsoncpp .............................. no
    protobuf ............................. no
    libxml2 and libxslt .................. no
    lcms2 ................................ no
    png .................................. yes
    JPEG ................................. no
    harfbuzz ............................. no
    freetype ............................. yes
    x11 .................................. yes
  Required system libraries:
    fontconfig ........................... yes
    dbus ................................. no
    nss .................................. no
    khr .................................. yes
    glibc ................................ yes
  Required system libraries for qpa-xcb:
    libdrm ............................... yes
    xcomposite ........................... no
    xcursor .............................. no
    xi ................................... yes
    xrandr ............................... no
    xtst ................................. no

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

Note: PKG_CONFIG_LIBDIR automatically set to /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/pkgconfig:/home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/share/pkgconfig:/home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/pkgconfig

Note: PKG_CONFIG_SYSROOT_DIR automatically set to /home/e381734/workspace/qt/cross-compile/debian/sysroot

Note: journald, syslog or slog2 integration is enabled.
If your users intend to develop applications against this build,
ensure that the IDEs they use either set QT_FORCE_STDERR_LOGGING to 1
or are able to read the logged output from journald, syslog or slog2.

Note: Disabling X11 Accessibility Bridge: D-Bus or AT-SPI is missing.

WARNING: QDoc will not be compiled, probably because libclang could not be located. This means that you cannot build the Qt documentation.

Either ensure that llvm-config is in your PATH environment variable, or set LLVM_INSTALL_DIR to the location of your llvm installation.
On Linux systems you may be able to install libclang from a package. On macOS you could use Homebrew's llvm package.
On Windows you need to set LLVM_INSTALL_DIR to the installation path.

Here is the xlib config test verbose output:

Using built-in specs.
COLLECT_GCC=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/bin/x86_64-linux-gnu-g++
COLLECT_LTO_WRAPPER=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/libexec/gcc/x86_64-linux-gnu/8.2.0/lto-wrapper
Target: x86_64-linux-gnu
Configured with: /home/e381734/workspace/toolchain/x86_64-linux-gnu-8.2.0/.build/x86_64-linux-gnu/src/gcc/configure --build=x86_64-build_pc-linux-gnu --host=x86_64-build_pc-linux-gnu --target=x86_64-linux-gnu --prefix=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0 --with-sysroot=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/x86_64-linux-gnu/sysroot --enable-languages=c,c++ --with-pkgversion='crosstool-NG 1.23.0.588-0364e3c' --enable-__cxa_atexit --disable-libmudflap --disable-libgomp --disable-libssp --disable-libquadmath --disable-libquadmath-support --disable-libsanitizer --enable-libmpx --with-gmp=/home/e381734/workspace/toolchain/x86_64-linux-gnu-8.2.0/.build/x86_64-linux-gnu/buildtools --with-mpfr=/home/e381734/workspace/toolchain/x86_64-linux-gnu-8.2.0/.build/x86_64-linux-gnu/buildtools --with-mpc=/home/e381734/workspace/toolchain/x86_64-linux-gnu-8.2.0/.build/x86_64-linux-gnu/buildtools --with-isl=/home/e381734/workspace/toolchain/x86_64-linux-gnu-8.2.0/.build/x86_64-linux-gnu/buildtools --disable-lto --with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++ -lm' --enable-threads=posix --enable-target-optspace --with-linker-hash-style=both --disable-plugin --disable-nls --disable-multilib --with-local-prefix=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/x86_64-linux-gnu/sysroot --enable-long-long --enable-multiarch
Thread model: posix
gcc version 8.2.0 (crosstool-NG 1.23.0.588-0364e3c) 
COMPILER_PATH=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/libexec/gcc/x86_64-linux-gnu/8.2.0/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/libexec/gcc/x86_64-linux-gnu/8.2.0/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/libexec/gcc/x86_64-linux-gnu/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/../../../../x86_64-linux-gnu/bin/
LIBRARY_PATH=/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/../../../../x86_64-linux-gnu/lib/../lib64/:/home/e381734/workspace/qt/cross-compile/debian/sysroot/lib/x86_64-linux-gnu/:/home/e381734/workspace/qt/cross-compile/debian/sysroot/lib/../lib64/:/home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/:/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/../../../../x86_64-linux-gnu/lib/:/home/e381734/workspace/qt/cross-compile/debian/sysroot/lib/:/home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-fuse-ld=gold' '-o' 'xlib' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
 /home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/libexec/gcc/x86_64-linux-gnu/8.2.0/collect2 --sysroot=/home/e381734/workspace/qt/cross-compile/debian/sysroot --eh-frame-hdr --hash-style=both -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -fuse-ld=gold -o xlib /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/crt1.o /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/crti.o /home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/crtbegin.o -L/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0 -L/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/../../../../x86_64-linux-gnu/lib/../lib64 -L/home/e381734/workspace/qt/cross-compile/debian/sysroot/lib/x86_64-linux-gnu -L/home/e381734/workspace/qt/cross-compile/debian/sysroot/lib/../lib64 -L/home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu -L/home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/../../../../x86_64-linux-gnu/lib -L/home/e381734/workspace/qt/cross-compile/debian/sysroot/lib -L/home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib -O1 main.o /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/libXext.so /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/libX11.so /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/libm.so -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /home/e381734/x-tools/x86_64-linux-gnu-gcc-8.2.0/lib/gcc/x86_64-linux-gnu/8.2.0/crtend.o /home/e381734/workspace/qt/cross-compile/debian/sysroot/usr/lib/x86_64-linux-gnu/crtn.o
/lib/x86_64-linux-gnu/libm.so.6: error: undefined reference to '__strtof128_nan', version 'GLIBC_PRIVATE'
collect2: error: ld returned 1 exit status

I checked the symbols in libm with :

strings ~/workspace/qt/cross-compile/debian/sysroot/lib/x86_64-linux-gnu/libm.so.6 | grep __strtof128_nan

and as the error says it's missing __strtof128_nan.

Any idea about this error ?

Thanks in advance,

X-Krys

[SGaist]

Hi,

Out of curiosity what is your host machine that you need to cross-compile to a x86_64 target ?

[X-Krys]

Actually it is also a x86_64 machine, it just about a cross OS compilation not a regular cross architecture compilation.

I know I could do a chroot build for instance but I guess it should be doable the cross compilation way.

Afterall it is just about a toolchain and a sysroot.

I'm trying to figure out what is the issue with my build environment that lead me to this error.

By the way just the xlib compilation seems to fail, I can still do the qt build but the xcb qpa backend will be skipped.

[SGaist]

The thing is, it seems to be looking at the libm.so.6 of your machine and not the one from the sysroot.