Thanks for your help! I back port that patch and build succesfully now. That patch is small enough so I sure it's suitable for backport.

At 2020-09-13 00:35:10, "Leo Famulari" <leo@famulari.name> wrote:
>On Sun, Sep 13, 2020 at 12:04:11AM +0800, Zhu Zihao wrote:
>> Hi everybody. I' m packaging digikam(https://digikam.org). A free photo management software from KDE project. There're 2 dependecies missing from current Guix(qtav & libksane)
>> 
>> 
>> I tried to package qtav(https://github.com/wang-bin/QtAV/) first, but it's latest release(v1.13.0) failed to build with Qt 5.14. And it was fixed in https://github.com/wang-bin/QtAV/commit/5abba7f0505e75fc. The question is: "Should I backport this fix to v1.13.0 or just use this commit to build qtav?"
>> 
>> 
>> If there're some guidelines on this, please tell me, thanks a lot!
>
>In general, we try to only package what upstream considers the "latest
>release".
>
>If the latest release doesn't work, we try to fix it in the smallest way
>that we can.
>
>So, in this case, that would mean trying to apply the patch you
>mentioned to the 1.13.0 release. If that works, great.
>
>Otherwise, we have to also consider the value of our own time, and it
>might be best to build the software based on the commit itself.
>
>Does that help?