message: Fixes for move prover options
  Closes:
diff: @@ -314,6 +314,7 @@ impl Options {
  .arg(
  Arg::with_name("generate-only")
  .long("generate-only")
  + .short("g")
  .help("only generate boogie file but do not call boogie"),
  )
  .arg(
  @@ -468,6 +469,11 @@ impl Options {
  .long("sequential")
  .help("whether to run the Boogie instances sequentially")
  )
  + .arg(
  + Arg::with_name("use-cvc4")
  + .long("use-cvc4")
  + .help("use cvc4 solver instead of z3")
  + )
  .after_help("More options available via `--config file` or `--config-str str`. \
  Use `--print-config` to see format and current values. \
  See `move-prover/src/cli.rs::Option` for documentation.");
  @@ -512,6 +518,9 @@ impl Options {
  _ => unreachable!("should not happen"),
  }
  }
  + if matches.is_present("generate-only") {
  + options.prover.generate_only = true;
  + }
  if matches.occurrences_of("sources") > 0 {
  options.move_sources = get_vec("sources");
  }
  @@ -593,6 +602,9 @@ impl Options {
  .unwrap()
  .parse::<usize>()?;
  }
  + if matches.is_present("use-cvc4") {
  + options.backend.use_cvc4 = true;
  + }
  if matches.is_present("print-config") {
  println!("{}", toml::to_string(&options).unwrap());
  Err(anyhow!("exiting"))
  