Q: There are build errors with Qt 5.*. A: If you are building the development branch you need to use Qt 6.7 or 6.8. If you prefer to install sioyek with a package manager, you can look at this list.
Primary reference: casio-fz1-data-structures.pdf (T. Sasaki, Casio R&D, March 1987). A clean machine-transcribed copy lives at casio-fz1-data-structures.md, useful for grep and side-by-side reading.