[Development] Coin, Boot2Qt, and OE_QMAKE_PATH_HOST_BINS variable

[Samuli Piippo]

On 09.01.2018 12:27, Konstantin Tokarev wrote:
> Hello,
> 
> I've tried to enable cross-compilation in Coin for QtWebKit 5.212 to improve
> platform coverage in each build, however I've faced following problem.
> 
> Our Linux cross-compilation platform is Boot2Qt which is based on meta-qt5
> Yocto layer. QtWebKit uses CMake internally, and Qt cmake config files on
> this platform rely on environment variable OE_QMAKE_PATH_HOST_BINS
> (see patch[1]). However, qmake-based builds seem to work fine without this
> variable.
> 
> I suppose that patch[1] is wrong. Can we revert it in Yocto images used in Coin?
> 
> 
> [1] https://github.com/meta-qt5/meta-qt5/blob/268429962056a12e0e899612dafb433c257af5cf/recipes-qt/qt5/qtbase/0006-Pretend-Qt5-wasn-t-found-if-OE_QMAKE_PATH_EXTERNAL_H.patch
> 
> You can see that this patch avtually checks OE_QMAKE_PATH_EXTERNAL_HOST_BINS
> CMake variable instead of environment; in
> sysroots/x86_64-pokysdk-linux/usr/share/cmake/OEToolchainConfig.cmake.d/OEQt5Toolchain.cmake
> this cmake variable is set to $ENV{OE_QMAKE_PATH_HOST_BINS}, there is no
> similar file for Aarch64 sysroot and there is no way to guess it's location in the build
> system without hardcoding. Anyway it won't help, because subject variable isn't set.
> 

Qmake based projects work in Coin since they do not use any of the Qt files
already present in the toolchain, but it seems cmake based projects now work
a bit differently. Even if we revert that patch, cmake would still be using
wrong files from the sysroot and not from the Qt it's testing against
in /home/qt/work/install/lib/cmake