Function leptonica_sys::convertFilesTo1bpp

pub unsafe extern "C" fn convertFilesTo1bpp(
    dirin: *const c_char, 
    substr: *const c_char, 
    upscaling: l_int32, 
    thresh: l_int32, 
    firstpage: l_int32, 
    npages: l_int32, 
    dirout: *const c_char, 
    outformat: l_int32
) -> l_ok