Can't build kdepim 16.08 due to errors building QtWebEngine

[David Jarvie]

I'm trying to build kdepim 16.08, based on Qt 5.6, but several modules won't 
build without QtWebEngine. The rest of Qt builds from source ok, but I've been 
trying for a few hours to get QtWebEngine to build without success. I've fixed 
various errors by installing dependencies, but this error remains:

make[3]: Entering directory '/home/david/src/git/qt5.6/qtwebengine/src/core'
/home/david/src/git/qt5.6/qtwebengine/src/3rdparty/ninja/ninja  -C 
/home/david/src/git/qt5.6/qtwebengine/src/core/Release
ninja: Entering directory 
`/home/david/src/git/qt5.6/qtwebengine/src/core/Release'
ninja: error: 
'/home/david/src/git/qt5.6/qtwebengine/src/3rdparty/chromium/third_party/yasm/source/config/linux/Makefile', 
needed by 
'obj/src/3rdparty/chromium/third_party/yasm/yasm.gen/third_party/yasm/module.c', 
missing and no known rule to make it
Makefile.gyp_run:863: recipe for target 'invoke_ninja' failed
make[3]: *** [invoke_ninja] Error 1
make[3]: Leaving directory '/home/david/src/git/qt5.6/qtwebengine/src/core'
Makefile:116: recipe for target 'sub-gyp_run-pro-make_first' failed
make[2]: *** [sub-gyp_run-pro-make_first] Error 2

As it says, 
qtwebengine/src/3rdparty/chromium/third_party/yasm/source/config/linux/Makefile 
hasn't been generated, but I don't know why.

Qt was obtained following the instructions at 
https://community.kde.org/Guidelines_and_HOWTOs/Build_from_source/OwnQt5 
(using --branch 5.6 for the git clone command).

Can anyone help?

-- 
David Jarvie.
KDE developer.
KAlarm author -- http://www.astrojar.org.uk/kalarm