[Development] Qt 5 and old versions of XCB

[Craig.Scott at csiro.au]

>>
>>
>>
>>Every Linux distro uses X.org, which uses XCB.
>>
>>
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>> Including openSUSE 11.1, but just any XCB is not enough. It needs to be
>>more recent than some version. For users with an incompatible version of
>>XCB, I think we can provide a better user experience than hitting
>>compiler errors when building Qt. If someone knows the minimum version
>>required, hopefully configure tests can check for it.
>>
>>While trying to upgrade XCB, I also found that OpenGL support was only
>>enabled if the xcb-xlib configuration test passed. I don't believe this
>>limitation was reported by the configuration output either.
>
>Feel free to provide patches for better diagnostic messages then.
>
>Solving the problem of old distro's is not that hard. All that's required
>is to link xcb statically into the platform plugin. This is something that
>can be done, it can even be made rather simply in the Qt build system.


Could be a good suggestion. How about a compromise? Since there are concerns around how many linux distros will be running a recent enough version of xcb, could a properly built static xcb library be provided as part of the Qt build itself (noting Thiago's follow-up comments about -fPIC)? A configure option could be provided for those who have to care about this (but it could be off by default). That should save ISV's a lot of headaches. Not sure if the xcb licensing terms would be compatible with Qt's, but on the face of it, it looks likely to be okay.


--
Dr Craig Scott
Computational Software Engineering Team Leader, CSIRO (CMIS)
Melbourne, Australia