Evaluate adding linuxdeployqt

[darkmattercoder]

It would also be nice to bundle linuxdeployqt with the Docker images. Linuxdeployqt also requires patchelf:
curl -sLO https://ftp.fau.de/debian/pool/main/p/patchelf/patchelf_0.8-2_amd64.deb
dpkg -i patchelf_0.8-2_amd64.deb

Newer patchelf versions apparantly cripples libQt5Core; NixOS/patchelf#124

Building linuxdeployqt
git clone https://github.com/probonopd/linuxdeployqt.git
cd linuxdeployqt && qmake && make && make install

Originally posted by @somlioy in #5 (comment)

[somlioy]

It is to be noted that linuxdeployqt technically does not support 18.04 until 2021, which is when 16.04 LTS no longer is supported.

We do not support linuxdeployqt on systems newer than the oldest Ubuntu LTS release
probonopd/linuxdeployqt#340;

The oldest supported LTS release is currently 16.04. They have however added a flag (-unsupported-allow-new-glibc) to allow the program to run with newer glibc version used on 18.04.

I'm not quite sure where the limitation lies, or if this was implemented just due to "best practice" reasons: "Build on old systems, run on newer systems"

Another possibility would be to use linuxdeploy with linuxdeploy-plugin-qt instead (as mentioned in Issue # 5), I however havent tried that if it is the case not supporting 18.04 aswell.

[haampie]

https://github.com/linuxdeploy/linuxdeploy + https://github.com/linuxdeploy/linuxdeploy-plugin-qt work great on Ubuntu 18.04. linuxdeployqt could in principle work as well, but the author (rightfully) has opinions you should create appimages linked against the oldest still supported glibc, meaning compiling from Ubuntu 16.04 indeed.

To ship linuxdeploy, it's enough to do

RUN wget -q https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-x86_64.AppImage -P /usr/local/bin && chmod +x /usr/local/bin/linuxdeploy-x86_64.AppImage

RUN wget -q https://github.com/linuxdeploy/linuxdeploy-plugin-qt/releases/download/continuous/linuxdeploy-plugin-qt-x86_64.AppImage -P /usr/local/bin && chmod +x /usr/local/bin/linuxdeploy-plugin-qt-x86_64.AppImage

and then package things like

QML_SOURCES_PATHS=to/your/qml linuxdeploy-x86_64.AppImage --appdir AppDir --plugin qt --output appimage