message: Add emit_u64 to Emitter API
diff: @@ -89,6 +89,8 @@ pub trait Emitter {
  fn get_label(&mut self) -> Self::Label;
  fn get_offset(&mut self) -> Self::Offset;
  + fn emit_u64(&mut self, x: u64);
  +
  fn emit_label(&mut self, label: Self::Label);
  fn emit_mov(&mut self, sz: Size, src: Location, dst: Location);
  @@ -490,6 +492,10 @@ impl Emitter for Assembler {
  self.offset()
  }
  + fn emit_u64(&mut self, x: u64) {
  + self.push_u64(x);
  + }
  +
  fn emit_label(&mut self, label: Self::Label) {
  dynasm!(self ; => label);
  }
  