@domenan: All the gory details you could ever want to know about my cross toolchains are in the x-tc package in the
Snapshots thread, but for a first foray into the abyss, the
KOReader frontend to that might be more approachable
.
EDIT: Possibly hard-dep on a Linux box/VM. macOS *might* work, but is not guaranteed to and may require some manual fiddling, and Win32 is... hellish, so, going with nope on that one.