> 3. tests of other packages may fail for the same reason.

Yes, I have got tiled running, and find that 'cool-retro-term' need to
be adjusted.

And vlc fails to build due to can't find headers of Qt5X11Extras.
Indeed, the pkg-config output of Qt5X11Extras seems wrong:
--8<---------------cut here---------------start------------->8---
$ pkg-config --cflags --libs Qt5X11Extras
-I/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/include/qt5/QtGui -I/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/include/qt5 -I/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/include/qt5/QtCore -I/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/include/qt5 -I/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/include/qt5/QtX11Extras -I/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/include/qt5 -L/gnu/store/l8xp2i57plmdd3pprhznc8r03ha3sv2s-qtbase-5.9.1/lib -lQt5X11Extras -lQt5Gui -lQt5Core
--8<---------------cut here---------------end--------------->8---

I can try fix this pkg-config issue.

>
> I'll take care of the packages in kde-frameworks.scm, I assume/hope
> Thomas will take care of the ones in kde.scm.

Yeah, I build 'kiarchive', and find it puts 'mkspecs' under $out, which
needs change to $out/lib/qt5/mkspecs.

>
> 宋文武, how can we coordinate the required changes? Should they go into one patch? Or into a series?

I think we could make a series patches, and can squash them later if
suitable.