Function dr_syscall_set_sysnum 

pub unsafe extern "C" fn dr_syscall_set_sysnum(
    drcontext: *mut c_void,
    new_num: c_int,
)

Usable only from a pre-syscall (dr_register_pre_syscall_event()) event, or from a post-syscall (dr_register_post_syscall_event()) event when also using dr_syscall_invoke_another(). Sets the system call number of the system call about to be invoked to \p new_num.