6.22.02 build failure with -Dx11=OFF

[cgleggett]

Describe the bug

When building 6.22.02 with x11 disabled, there's a build error:

CMakeFiles/RGL.dir/src/TGLFormat.cxx.o: In function `TGLFormat::InitAvailableSamples()':
TGLFormat.cxx:(.text+0x35c): undefined reference to `XGetVisualInfo'
TGLFormat.cxx:(.text+0x476): undefined reference to `XFree'
CMakeFiles/RGL.dir/src/TGLWidget.cxx.o: In function `TGLWidget::CreateWindow(TGWindow const*, TGLFormat const&, unsigned int, unsigned int, std::pair<void*, void*>&)':
TGLWidget.cxx:(.text+0xcd5): undefined reference to `XCreateColormap'
TGLWidget.cxx:(.text+0xd28): undefined reference to `XCreateWindow'
CMakeFiles/RGL.dir/src/TGLWidget.cxx.o: In function `TGLWidget::~TGLWidget()':
TGLWidget.cxx:(.text+0x1765): undefined reference to `XFree'
collect2: error: ld returned 1 exit status
make[2]: *** [lib/libRGL.so] Error 1
make[1]: *** [graf3d/gl/CMakeFiles/RGL.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....

Expected behavior

a clean build

To Reproduce

setup gcc 9.2.0
> export CXX=g++
> export CC=gcc
> cmake -Dx11=OFF -DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_EXTENSIONS=Off ../src
> make -j30

Setup

version: v6.22.02
OS: RHEL7
root built from git source (tag v6-22-02)
gcc: 9.2.0

[couet]

Is it new problem with 6.22 ? This code (TGLFormat) is not recent and has not been changed recently.
The error messages you get would suggest X11 is not properly installed (or not found by the ROOT
install procedure) on your machine.

[oshadura]

@cgleggett could you please post a CMake configuration log? Thanks!

[oshadura]

Ah this issue is known https://sft.its.cern.ch/jira/browse/ROOT-10640 and in fact, I opened pr to fix it some time ago #5524. I will finish it and backport it to 6.22 as well.

[oshadura]

@cgleggett I forgot to add that as a temporary fix you can just disable as opengl well.

[cgleggett]

it wasn't there in 6.14.08 - I haven't tried anything in between.

This is on a host which has no X libraries installed (an HPC), and installing them myself is a non-starter.

I did rebuild successfully with -Dopengl=off

[oshadura]

It is fixed in #5524