DT-540: Fix segmentation fault in Snap Store
requested to merge sergio-costas/gnome-software:DT-540-snap-store-fails-with-a-core-dump-if-the-language-is-differen-to-to-en-us into snap-store-41
Some users reported that the Snap Store crashes with a segmentation fault. The bug was a double-free memory bug, which, being on a GObject (which requires reading some data in the memory block to be free before freeing it), resulting in an invalid memory access.
This patch fixes it by compiling LIBXMLB directly instead of relying on the other parts to download and compile it. It also fixes the version to 0.3.9 and applies a patch for the double-free bug.
That patch has also been sent upstream.
Fix https://bugs.launchpad.net/snap-store-desktop/+bug/1988440