\version "2.19.3"

\markup "align left"
\score{
  \relative f'' { e4 e e \mark BLA e }
  \layout{
    \override Score.RehearsalMark #'self-alignment-X = #LEFT
    line-width = 100\mm
    ragged-right=##f
  }
}

\markup "align center"
\score{
  \relative f'' { e4 e e \mark BLA e }
  \layout{
    \override Score.RehearsalMark #'self-alignment-X = #CENTER
    line-width = 100\mm
    ragged-right=##f
  }
}

\markup "align right"
\score{
  \relative f'' { e4 e e \mark BLA e }
  \layout{
    \override Score.RehearsalMark #'self-alignment-X = #RIGHT
    line-width = 100\mm
    ragged-right=##f
  }
}