Calibre is my favorite e-book library management program. My repository contains a package for Calibre 4.x which works well, but it is using Python2 and has been superseded since September 2020 by the new 5.x releases which are based on Python3.
I have been postponing the Slackware package migration from 4.x to 5.x until Slackware 15.0 would be released, since the move from Python 2 to 3 promised to be a significant effort in terms of changing the calibre.SlackBuild script.

Now that Slackware 15.0 is available, I decided to pick up this chore and re-write the build script to support Calibre 5.x. The re-write took several days because of all the new Python modules that are now required by Calibre 5.
I have dropped support for embedding a copy of the Qt5 libraries and compiling an embedded Python interpreter is no longer optional. It simplified the script and reduced the compile-time a lot (no more Qt5 compilation).

Now the bad part. I have been trying to compile Calibre 5.38 on Slackware 15.0 now for the past week. Well, compiling is OK, and the ebook viewer and editor work properly. But the main calibre program crashes with an error “free(): invalid pointer” as soon as it tries to create a new (or read an existing) Calibre database (metadata.db). As a consequence, the Calibre library maintenance program is completely useless.
I have not found a cause for that, and unfortunately the Calibre developer refuses to discuss any bug that is not in his own pre-built binaries.

So I am between a rock and a hard place. I have no idea how to proceed from here, and I am not willing to add a non-functional package to my repository. So I have uploaded my work here:

If anyone wants to try this out and finds the cause of the crash bug, please share your thoughts here.

Thanks, Eric