Jonas, this alignment issue was reported on Sparc64. It was recently addressed by upstream, but not yet brought into Debian. Mentioning in case there is any interaction with the Rust bindings, which were also throwing an error related to alignment.
https://github.com/DanBloomberg/leptonica/issues/750 https://ci.debian.net/packages/r/rust-leptonica-sys/testing/i386/52950971/#S7
