On Ubuntu host, build succeeded; but e.g. on Manjaro host, it failed with:
```
./build.sh: line 233: /opt/electrum/contrib/build-linux/appimage/../../../contrib/build-linux/appimage/.cache/appimage/appimagetool: No such file or directory
```
This slightly increases the AppImage size but allows us to be more
compatible with older distributions.
-----
taken from Electron-Cash/Electron-Cash@96644acd6f
It warns about scripts being installed in a location that is not on the
path, but that is inconsequential as they are not used.
-----
taken from Electron-Cash/Electron-Cash@9a29017c5d
When building in docker on macOS, python builds with .exe extension
because the case insensitive file system of macOS leaks into docker.
This causes the build to result in a different output on macOS compared
to Linux. We simply patch sysconfigdata to remove the extension.
Some more info: https://bugs.python.org/issue27631
There are a lot of dupliacted files, testing files and unused libraries
present in the AppImage. Removing these reduces the AppImage size
significantly.
-----
taken from Electron-Cash/Electron-Cash@cff5fb1289
There was a problem where Python would not properly include the faketime
timestamp sometimes. This patch replaces faketime with a patch that is
used by Ubuntu for reproducible builds by exporting BUILD_DATE and
BUILD_TIME with the desired values.
-----
taken from Electron-Cash/Electron-Cash@9532508a3f
We build our own mksquashfs from squashfskit which supports generating
reproducible squashfs images. We use a small wrapper script to remove
the -mkfs-fixed-time which appimagekit passes but squashfskits
mksquashfs does not support.
-----
taken from Electron-Cash/Electron-Cash@dd1f106f4f
see AppImage/AppImageKit#929
pkg2appimage excludes libusb-1.0.so by default for no good reason:
83483c2971/excludelist (L112)
This can cause an issue when the AppImage loads the systems libusb but the
systems libusb in turn loads libudev from the AppImage. The kernel ABI for
libusb will not be changing so it is safe to bundle it into the AppImage.
-----
taken from Electron-Cash/Electron-Cash@25d45fdcbf
