Add missing fstream include

[miquelmassot]

No description provided.

[miquelmassot]

FYI the compilation error has nothing to do with the current PR:

g2o_qglviewer.cpp:81:25: error: invalid user-defined conversion 
from 
‘Qt::WindowFlags’ {aka ‘QFlags<Qt::WindowType>’} 
to 
‘const QGLWidget*’ [-fpermissive]

[RainerKuemmerle]

FYI the compilation error has nothing to do with the current PR:

g2o_qglviewer.cpp:81:25: error: invalid user-defined conversion 
from 
‘Qt::WindowFlags’ {aka ‘QFlags<Qt::WindowType>’} 
to 
‘const QGLWidget*’ [-fpermissive]

Thanks. I need to revisit this and setup CI for the pymem branch. I broke this by accident while trying to avoid a deprecation warning from libqglviewer.

[miquelmassot]

I am hitting a different error in my CI - could I get your eyes into this?
https://github.com/miquelmassot/g2o-python/actions/runs/7101323340/job/19329185672#step:4:279

[RainerKuemmerle]

@miquelmassot I saw you changed CI on the master branch. Did it resolve the issue?
The above job did not install libeigen explicitly. The reshaped method got added in Eigen 3.4. I wanted to push a change to the pymem branch to reflect this min version requirement.

[miquelmassot]

Noted - I arranged that too - but I might be missing something else:

In step:4:176 I am installing Eigen 3.4 but in step:7:558 states that only 3.3.7 is found... I think I am missing something in GHA.

[RainerKuemmerle]

Seems like https://github.com/miquelmassot/g2o-python/actions/runs/7126447254/job/19404355975#step:7:91 is starting some container where then only an older version of Eigen is available?

Reading the docs of this ci tool, seems like we can use https://cibuildwheel.readthedocs.io/en/stable/options/#before-build to specify commands to be run in the container? But I am not really sure here.