New comment by Johnnynator on void-packages repository

https://github.com/void-linux/void-packages/pull/11891#issuecomment-506920374
Comment:
@pullmoll Do you have an idea how we could fix our qmake build-style/qmake for cross compiling that wouldn't be a tremendous amount of work?

Longer version:
A qmake binary only ever supports one target and has things like `QT_SYSROOT` and `QT_INSTALL_LIBS` hardcoded in the resulting binary so they can't be overwritten at runtime by a config file or flag. There are only 4 options to solve this for Void visivle for me:

- Build qtbase two times for every cross target, once as cross packages as currently and a 2nd with the same config for the host and only grab qmake out of there (wastes a ton of ressources on the builder)
- Add a way for xbps-src to spill out a cross target package and a build arch package (probably quite complex, and would (at least currently) only be needed for qt)
- manually mess with the provided Makefile (probably the easiest way)
`make EXTRA_CXXFLAGS="-I/usr/include/qt5/QtCore/5.13.0/QtCore -I/usr/include/qt5/QtCore/5.13.0 -I/usr/include/qt5/QtCore -I/usr/include/qt5/ -DQMAKE_OPENSOURCE_VERSION" QT_MAJOR_VERSION=5 QT_MINOR_VERSION=13 QT_PATCH_VERSION=0 QT_VERSION=5.13.0 SOURCE_PATH=.. QMAKESPEC=/usr/lib/qt5/mkspecs/linux-aarch64-gnu-g++ BUILD_PATH=. RM_F="rm -rf" EXTRA_LFLAGS="-lQt5Bootstrap"  -f Makefile.unix` gives an unconfigured qmake
- Make the 107 packages that use the qmake build-style nocross