custom-tuning causes fatal error

[pls]

Hey all,

I tried to compile the following two snippets from the NR:

%%%%%%%% snippet 1 %%%%%%%%
mynotes = {
  c'4 e' g' c'' |
  e''4 g'' b'' c'''
}

<<
  \new Staff {
    \clef treble
    \mynotes
  }
  \new TabStaff {
    \contextStringTuning #'custom-tuning <c' g' d'' a''>
    \mynotes
  }
>>
%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%% snippet 2 %%%%%%%%%
\makeStringTuning #'custom-tuning <c' g' d'' a''>

mynotes = {
  c'4 e' g' c'' |
  e''4 g'' b'' c'''
}

<<
  \new Staff {
    \clef treble
    \mynotes
  }
  \new TabStaff {
    \set TabStaff.stringTunings = #custom-tuning
    \mynotes
  }
>>
%%%%%%%%%%%%%%%%%%%%%%

Both of them crash with a fatal error:

GNU LilyPond 2.15.19
Processing `custom-tuning.ly'
Parsing...
custom-tuning.ly:577:4: error: unknown escaped string: `\contextStringTuning'
    
    \contextStringTuning #'custom-tuning <c' g' d'' a''>
custom-tuning.ly:577:4: error: syntax error, unexpected STRING
    
    \contextStringTuning #'custom-tuning <c' g' d'' a''>
custom-tuning.ly:571:0: error: errors found, ignoring music expression

<<
fatal error: failed files: "custom-tuning.ly"


HTH,
patrick