Function mupdf_sys::fz_install_load_system_font_funcs

pub unsafe extern "C" fn fz_install_load_system_font_funcs(
    ctx: *mut fz_context,
    f: fz_load_system_font_fn,
    f_cjk: fz_load_system_cjk_font_fn,
    f_fallback: fz_load_system_fallback_font_fn
)

Install functions to allow MuPDF to request fonts from the system.

Only one set of hooks can be in use at a time.